Name: how ka and kb show acid-base strength
Uploaded: 2020-09-24T15:06:51.000Z
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relative-strengths-of-conjugate-acid-base-pairs

Relative Strengths of Conjugate Acid-Base Pairs

היחס בין קבועי הפירוק של זוג חומצה-בסיס מצומדים יכול להיות מבוטא כמותית. בחומצה חלשה, HA, קבוע הפירוד החומצי, Ka, מבוטא כריכוז יוני ההידרוניום כפול ריכוז יוני A חלקי הריכוז של HA.קבוע בסיס הפירוק, Kb, של בסיס הצמוד שלו, יון A, מבוטא כריכוז HA כפול ריכוז יוני ההידרוקסיד חלקי ריכוז יון A.אם הביטויים של Ka ו-Kb מוכפלים, המשוואה שנוצרת היא ביטוי שיווי המשקל של Kw.משוואה זו מראה ש-Ka של החומצה החלשה ו-Kb של הבסיס הצמוד שלה נמצאים ביחס הפוך. לחומצה חזקה יותר, עם Ka גבוה יותר, תמיד יש בסיס צמוד חלש יותר ביחס ישר עם Kb נמוך יותר וההפך.מכיוון שהערך של Kw הוא קבוע, המשוואה הזו יכולה לשמש לחישוב Ka או Kb של צמד חומצה-בסיס מצומד אם אחד מהם ידוע. לדוגמה, אם ה-Kb של בסיס הוא 1 כפול 10 בחזקת מינוס 6, ניתן לחשב שה-Ka של החומצה המצומדת יהיה 1 כפול 10 בחזקת מינוס 8. את היחס בין Ka לבין Kb ו-Kw ניתן לבטא כלוגריתם שלילי, pKa, pKb ו-pKw.במשוואה Ka כפול Kb שווה Kw, כשמחשבים את הלוגריתם השלילי משני הצדדים, המשוואה שמתקבלת היא pKa ועוד pKb שווה ל-pKw, שהוא 14 ב-25 מעלות צלזיוס. ניתן להשתמש ב-pKa ו-pKb להשוואת חוזק וחולשה של חומצות ובסיסים. ככל שערך ה-pKa נמוך, החומצה חזקה יותר.באופן דומה, ככל שערך ה-pKb נמוך יותר, הבסיס חזק יתר. לדוגמה, חומצה עם pKa של 2.1 חזקה מחומצה עם pKa של 4.6.

חוזקות יחסיות של זוגות חומצה-בסיס מצומדים

<div style="direction:rtl">כימיה של חומצה-בסיס של ברונסטד-לאורי היא העברת פרוטונים; לפיכך, ההיגיון מציע קשר בין החוזקות היחסיות של זוגות חומצה-בסיס מצומדים. חוזקה של חומצה או בסיס נמדד בקבוע היינון שלה, Ka או Kb, המייצג את היקף תגובת היינון החומצה או הבסיס. עבור זוג החומצה-בסיס המצומד HA / A−, משוואות שיווי המשקל היינון וביטויי קבוע היינון הם: <img alt="Eq1" src="/files/ftp_upload/11398/11398_Equation_1.png" style="height: 90px;"> <img alt="Eq2" src="/files/ftp_upload/11398/11398_Equation_2v2.png" style="height: 70px;"> הוספת שתי המשוואות הכימיות הללו מניבה את המשוואה לאוטויוניזציה למים: <img alt="Eq3" src="/files/ftp_upload/11398/11398_Equation_3.png" style="height: 50px;"> כפי שצוין קודם לכן, קבוע שיווי המשקל עבור תגובה מסוכמת שווה למכפלה המתמטית של קבועי שיווי המשקל עבור התגובות שנוספו, וכך <img alt="Eq4" src="/files/ftp_upload/11398/11398_Equation_4.png" style="height: 90px;"> משוואה זו מציינת את הקשר בין קבועי יינון עבור כל זוג חומצה-בסיס מצומד, כלומר, המכפלה המתמטית שלהם שווה לתוצר היונים של מים, KW. על ידי ארגון מחדש של משוואה זו, מתגלה קשר הדדי בין החוזקות של זוג חומצה-בסיס מצומד: <img alt="Eq5" src="/files/ftp_upload/11398/11398_Equation_5.png" style="height: 90px;"> הקשר היחסי ההפוך בין Ka ל-Kb פירושו שככל שהחומצה או הבסיס חזקים יותר, כך השותף המצומד שלו חלש יותר. אם לוקחים את הלוגריתם השלילי של שני הצדדים של המשוואה, Ka × Kb = KW מניבה <img alt="Eq6" src="/files/ftp_upload/11398/11398_Equation_6.png" style="height: 50px;"> לאחר מכן <img alt="Eq7" src="/files/ftp_upload/11398/11398_Equation_7.png" style="height: 50px;"> מכיוון ש-pKW הוא 14 ב-25 מעלות צלזיוס, ניתן לכתוב את המשוואה הזו גם כ <img alt="Eq1" src="/files/ftp_upload/11398/11398_Equation_8.png" style="height: 50px;"> ה- pKa ו- pKb מייצגים גם את החוזק של חומצות ובסיסים, בהתאמה. כמו pH ו-pOH, ככל שהערך pKa או pKb גבוה יותר, כך החומצה או הבסיס חלשים יותר, בהתאמה. <table style="margin-left: auto; margin-right: auto;"> <tbody> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה</td> <td style="color: black; border: 1px solid black; text-align: center;">בסיס</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה פרכלורית (HClO4)*</td> <td style="color: black; border: 1px solid black; text-align: center;">יון פרכלוראט (ClO4−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה גופרתית(H2SO4)*</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון מימן גופרתי(HSO4−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יוד מימן (HI)*</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון יוד(I−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן ברומיד (HBr)*</td> <td style="color: black; border: 1px solid black; text-align: center;">יון ברומיד(Br−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן כלורי (HCl)*</td> <td style="color: black; border: 1px solid black; text-align: center;">יון כלוריד(Cl−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה חנקתית(HNO3)*</td> <td style="color: black; border: 1px solid black; text-align: center;">יון חנקתי(NO3−)**</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יון הידרוניום (H3O+)</td> <td style="color: black; border: 1px solid black; text-align: center;">מים(H2O)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יון מימן גופרתי (HSO4−)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון סולפט (SO42−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה זרחתית(H3PO4)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון דימימן פוספט (H2PO4−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן פלואוריד(HF)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון פלואוריד(F−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה חנקתית(HNO2)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון ניטריט(NO2−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה אצטית(CH3CO2H)</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון אצטט(CH3CO2−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">חומצה פחמית (H2CO3)</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון מימן פחמתי(HCO3−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן גופרתי (H2S)</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון מימן גופרתי (HS−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יון אמוניום (NH4+)</td> <td style="color: black; border: 1px solid black; text-align: center;"> אמוניה (NH3)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן ציאניד (HCN)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון ציאניד (CN−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יון מימן פחמתי(HCO3−)</td> <td style="color: black; border: 1px solid black; text-align: center;">יון קרבונט (CO32−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מים (H2O)</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון הידרוקסיד (OH−)</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">יון מימן גופרתי (HS−)†</td> <td style="color: black; border: 1px solid black; text-align: center;">יון גופרתי(S2−)‡</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">אתנול (C2H5OH)†</td> <td style="color: black; border: 1px solid black; text-align: center;"> יון אתוקסיד(C2H5O−)‡</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">אמוניה(NH3)†</td> <td style="color: black; border: 1px solid black; text-align: center;">יון אמיד(NH2−)‡</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מימן (H2)†</td> <td style="color: black; border: 1px solid black; text-align: center;">יון הידריד (H−)‡</td> </tr> <tr> <td style="color: black; border: 1px solid black; text-align: center;">מתאן(CH4)†</td> <td style="color: black; border: 1px solid black; text-align: center;">יון מתיד(CH3−)‡</td> </tr> <tr> <td colspan="2" style="color: black; border: 1px solid black; ">*לעבור יינון חומצה מלא במים</td> </tr> <tr> <td colspan="2" style="color: black; border: 1px solid black; ">† אינו עובר יינון חומצה במים</td> </tr> <tr> <td colspan="2" style="color: black; border: 1px solid black; ">**אינו עובר יינון בסיס במים</td> </tr> <tr> <td colspan="2" style="color: black; border: 1px solid black; ">‡לעבור יינון בסיס מלא במים</td> </tr> </tbody> </table> הרשימה של זוגות חומצה-בסיס מצומדים המוצגים מסודרת כדי להראות את החוזק היחסי של כל מין בהשוואה למים. בעמודת החומצה, המינים הרשומים מתחת למים הם חומצות חלשות יותר ממים. מינים אלה אינם עוברים יינון חומצה במים; הן אינן חומצות בורנסטד-לאורי. כל המינים המפורטים מעל המים הם חומצות חזקות יותר, המעבירות פרוטונים למים במידה מסוימת כשהם מומסים בתמיסה מימית ליצירת יוני הידרוניום. מינים מעל המים אך מתחת ליון הידרוניום הם חומצות חלשות, העוברות יינון חומצי חלקי, ואילו אלו שמעל יון הידרוניום הינן חומצות חזקות המיוננות לחלוטין בתמיסה מימית. טקסט זה מותאם מ<a href="https://openstax.org/books/chemistry-2e/pages/14-3-relative-strengths-of-acids-and-bases"> Openstax, Chemistry 2e, Section 14.3: </a><a href="https://openstax.org/books/chemistry-2e/pages/14-3-relative-strengths-of-acids-and-bases">Relative Strengths of Acids and Bases</a>.</div>

כימיה של בסיס חומצה Brønsted-Lowry היא העברה של פרוטונים; לפיכך, ההיגיון מציע קשר בין העוצמות היחסיות של בסיס חומצה מצומד ...

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how ka and kb show acid-base strength

Brønsted-Lowry acid-base chemistry is based on proton transfer. That idea helps show how the strength of an acid is linked to the strength of its conjugate base, and vice versa. Acid and base strength is measured with ionization constants, Ka and Kb, which tell how far an ionization reaction goes.

For the conjugate pair HA and A−, the acid ionizes in water and the base reaction can be written for the partner species. When the two reactions are added, they give the autoionization of water. The equilibrium constant for the summed reaction is the product of the two individual constants, so Ka × Kb = Kw for any conjugate acid-base pair.

This relationship shows a reciprocal pattern. If one member of the pair is stronger, its conjugate partner is weaker. The stronger the acid, the weaker its conjugate base, and the stronger the base, the weaker its conjugate acid.

Taking the negative log of Ka × Kb = Kw gives the pKa and pKb form of the same idea. At 25 °C, pKw is 14, so the relationship can also be written as pKa + pKb = 14. Like pH and pOH, a larger pKa or pKb means a weaker acid or base.

The conjugate acid-base list is arranged to compare each species with water. Species below water in the acid column are weaker acids than water, so they do not undergo acid ionization in water and are not Brønsted-Lowry acids. Species above water transfer protons to water to some extent and form hydronium ions.

Among those acids, the ones above water but below hydronium ion are weak acids, so they ionize only partially in aqueous solution. The acids above hydronium ion are strong acids, and they are completely ionized in water. The list includes examples such as perchloric acid, sulfuric acid, hydrogen chloride, nitric acid, acetic acid, ammonia, ethanol, hydride, and methane with their conjugate partners.

How Ka and Kb Show Acid-Base Strength

bronsted-lowry acids and bases

Proton Transfer in Acids and Bases

Acids and bases can be understood through proton transfer. Early scientists described acids by their sour taste, their effect on dyes, and their reaction with limestone, which releases carbon dioxide. Robert Boyle also noted that acid solutions can lose these properties after contact with alkali, or base, solutions. The modern view developed step by step. Humphry Davy showed that hydrogen is the essential part of acids. Joseph Louis Gay-Lussac then described acids as substances that neutralize...

water: a bronsted-lowry acid and base

Water as an Amphiprotic Substance

Water can act as both a Brønsted-Lowry acid and a Brønsted-Lowry base. When hydrogen fluoride dissolves in water, it donates protons to water. This is acid ionization. The products are hydronium ions and fluoride ions. Water can also accept protons from another substance. When pyridine dissolves in water, it accepts a proton from water molecules. This is base ionization. The products are hydroxide ions and pyridinium ions. These reactions show that water can play either role. A substance that...

ph scale

pH and pOH in Water

pH and pOH show how hydronium and hydroxide ions behave in water and other aqueous solutions. These ion concentrations are linked by the ion product of water, K w , so when one goes up, the other goes down. Because ion concentrations can differ by huge amounts, a logarithmic scale is used to describe them. pH is defined from the hydronium ion concentration, [H3O+], and pOH is the matching p-function for hydroxide ion concentration. These two values are also connected through the K w...

relative strengths of conjugate acid-base pairs

Brønsted-Lowry acid-base chemistry is based on proton transfer. That idea helps show how the strength of an acid is linked to the strength of its conjugate base, and vice versa. Acid and base strength is measured with ionization constants, Ka and Kb, which tell how far an ionization reaction goes. For the conjugate pair HA and A−, the acid ionizes in water and the base reaction can be written for the partner species. When the two reactions are added, they give the autoionization of water. The...

strong acid and base solutions

Strong Acids, Strong Bases, and pH

Strong acids and strong bases change the pH of a solution by dissociating completely in water. A strong acid produces hydronium ions, which are H3O+ ions, and a strong base produces hydroxide ions, OH-. Because the dissociation is complete, the ion concentration can be found from the starting concentration and the molar ratio. For example, 0.20 M hydrobromic acid dissociates fully in water. It produces 0.20 M hydronium ions and 0.20 M bromide ions. A 0.015 M KOH solution also dissociates...

weak acid solutions

Weak Acid Equilibrium in Water

Weak acid equilibrium in water explains why many acids only partially react when dissolved. Most weak acid molecules stay in their original form, and only a small amount of hydronium ions forms. Weak acids are common in nature. They help create the tangy taste of citrus fruits, the stinging sensation from insect bites, and the smells linked to body odor. Acetic acid is a familiar weak acid. It is the main ingredient in vinegar. Its equation uses a double arrow to show that the reaction with...

weak base solutions

Weak Base pH and Kb Calculations

Weak base pH and Kb calculations show how partially reacting bases change water chemistry. Weak bases produce hydroxide ions when they dissolve by reacting with water molecules. Because the reaction only happens partly, these compounds are classified as weak bases. Weak bases are common in nature and in technology. Ammonia is one major example. Global production of ammonia is typically well over 100 metric tons each year. It is used as an agricultural fertilizer, a starting material for...

mixtures of acids

pH of Acid Mixtures

The pH of acid mixtures depends on the acids present, their dissociation constants, and their starting concentrations. When a solution contains two different acids, the pH can be found by choosing the method that fits their relative strengths. This makes acid mixtures a useful case for applying acid-base rules in chemistry. In a mixture of a strong acid and a weak acid, the strong acid dissociates completely and supplies almost all of the hydronium ions in the solution. The weak acid...

ions as acids and bases

Salt Hydrolysis and pH of Solutions

Salt hydrolysis explains why some salt solutions are acidic, basic, or neutral. Salts are ionic compounds made of cations and anions. In water, either ion may react with water through an acid or base ionization reaction. The pH of the solution depends on the relative acid-base strength of the ions in the salt. Ammonium chloride is a good example of an acidic salt. When it dissolves, it separates into ammonium ions and chloride ions. The ammonium ion is the conjugate acid of ammonia, so it can...

determining the ph of salt solutions

Salt Hydrolysis and pH in Solutions

Salt hydrolysis and pH in solutions depend on the ions released when a salt dissolves. Some ions react with water, while others do not. The balance between the cation and anion helps show whether the solution becomes acidic, basic, or neutral. Salts with pH-neutral anions and cations that produce hydronium ions give acidic solutions with pH below 7. Ammonium nitrate is one example. In NH4NO3, NO3− does not react with water, but NH4+ forms hydronium ions, so the solution is acidic. Other salts...

acid/base strengths and dissociation constants

acidbase-strengths-and-dissociation-constants

Acid and Base Strength in Water

Acid and base strength in water depends on how much a substance ionizes after it dissolves. If ionization is nearly complete, the substance is called strong. If only a small amount ionizes, it is called weak. Weak acids and weak bases are much more common than strong ones. The most common strong acids are HClO4, HCl, HBr, HI, HNO3, and H2SO4. The most common strong bases are LiOH, NaOH, KOH, Ca(OH)2, Sr(OH)2, and Ba(OH)2. These strong acids and bases ionize essentially completely in water. <br...

polyprotic acids

Stepwise Ionization of Polyprotic Acids

Polyprotic acids lose hydrogen ions in steps. The number of ionizable protons in a molecule determines whether an acid is monoprotic, diprotic, or triprotic. This video also shows that polyprotic bases can accept more than one proton. Monoprotic acids have one ionizable hydrogen atom per molecule. Examples include HCl, HNO3, and HCN. Their reactions with water form hydronium ions and the matching anion. Acetic acid, CH3CO2H, is also monoprotic because only the hydrogen in the carboxyl group...

acid strength and molecular structure

How Bonding Affects Acid Strength

Acid strength depends on bonding, electronegativity, and oxidation number. These factors help explain why some hydrogen compounds act as strong acids, while others behave as weak acids or bases. For binary acids, which are hydrogen compounds with one other nonmetal, acidity increases as the H-A bond gets weaker down a group. That is why the order for group 17 is HF &lt; HCl &lt; HBr &lt; HI, and for group 16 it is H2O &lt; H2S &lt; H2Se &lt; H2Te. Across a period, acid strength increases as...

lewis acids and bases

Electron-Pair Reactions in Acid-Base Chemistry

Electron-pair reactions explain Lewis acid-base chemistry. In 1923, G. N. Lewis described acids and bases by how they accept or donate a pair of electrons. When that electron pair forms a coordinate covalent bond, one atom supplies both bonding electrons. This bond is also called a dative bond. A simple example is the reaction of water with a hydrogen ion to make a hydronium ion. Ammonia can also combine with a hydrogen ion to form an ammonium ion. In both cases, the reaction creates a Lewis...

key terms and concepts

See how Ka, Kb, pKa, and pKb reveal the strength of conjugate acid-base pairs, including why stronger acids have weaker conjugate bases.

How Ka and Kb Show Acid-Base Strength | JoVE K12

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In science, a law is defined as a concise, verbal or mathematical, statement that summarizes a vast number of experimental observations. ...

The Scientific Method

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

Use models to explain how the scientific understanding of atomic structure has evolved.

PS.Chm.1.1

Radioactivity and Nuclear Equations

Nuclear chemistry is the study of reactions that involve changes in nuclear structure. The nucleus of an atom is composed of protons and, except for ...

Types of Radioactivity

The most common types of radioactivity are &#945; decay, &#946; decay, &#947; decay, neutron emission, and electron capture.
Alpha (&#945;) decay is the ...

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10&#8722;15 meters, a nucleus is ...

Nuclear Binding Energy

The difference between the calculated and experimentally measured masses is known as the mass defect of the atom. In the case of helium-4, the mass defect ...

Radioactive Decay and Radiometric Dating

Radioactivity is a spontaneous disintegration of an unstable nuclide and is a random process, as all the nuclei in the sample do not decay simultaneously. ...

Nuclear Fission

Many heavier elements with smaller binding energies per nucleon can decompose into more stable elements that have intermediate mass numbers and larger ...

Nuclear Power

Controlled nuclear fission reactions are used to generate electricity. Any nuclear reactor that produces power via the fission of uranium or plutonium by ...

Nuclear Fusion

The process of converting very light nuclei into heavier nuclei is also accompanied by the conversion of mass into large amounts of energy, a process ...

Nuclear Transmutation

Nuclear transmutation is the conversion of one nuclide into another. It can occur by the radioactive decay of a nucleus, or the reaction of a nucleus with ...

Use models to compare nuclear reactions including alpha decay, beta decay and gamma decay; nuclear fusion and nuclear fission.

PS.Chm.1.2

Atomic Orbitals

An atomic orbital represents the three-dimensional regions in an atom where an electron has the highest probability to reside. The radial distribution ...

The Pauli Exclusion Principle

The arrangement of electrons in the orbitals of an atom is called its electron configuration. We describe an electron configuration with a symbol that ...

The Energies of Atomic Orbitals

In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are ...

The Aufbau Principle and Hund's Rule

To determine the electron configuration for any particular atom, we can build the structures in the order of atomic numbers. Beginning with hydrogen, and ...

electron-configuration-of-multielectron-atoms

Electron Configuration of Multielectron Atoms

The alkali metal sodium (atomic number 11) has one more electron than the neon atom. This electron must go into the lowest-energy subshell available, the ...

Use models to explain how electrons are distributed in atoms.

PS.Chm.1.3

Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

The Periodic Table

As early chemists discovered more elements, they realized that various elements could be grouped by their similar chemical behaviors. One such grouping ...

Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

Use the Periodic Table as a model to predict the relative properties of elements based on the pattern of valence electrons in the outermost energy levels of atoms.

PS.Chm.2.1

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Construct an explanation to infer the atomic size, reactivity, electronegativity, and ionization energy of an element based on its position in the Periodic Table.

PS.Chm.2.2

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Lewis Symbols and the Octet Rule

Chemical bonds are complex interactions between two or more atoms or ions, which reduce the potential energy of the molecule. Gilbert N. Lewis developed a ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

Lattice Energy&#xA0;

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

trends-in-lattice-energy-ion-size-and-charge

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Resonance

The Lewis structure of a nitrite anion (NO2&minus;) may actually be drawn in two different ways, distinguished by the locations of the N-O and N=O ...

Formal Charges

In some cases, there are seemingly more than one valid Lewis structures for molecules and polyatomic ions. The concept of formal charges can be used to ...

Exceptions to the Octet Rule

Many covalent molecules have central atoms that do not have eight electrons in their Lewis structures. These molecules fall into three categories:


	...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Analyze and interpret data to explain the mechanisms and properties of the two main types of intramolecular (ionic and covalent) bonds.

PS.Chm.3.1

Analyze the structure of atoms and isotopes.

How Ka and Kb Show Acid-Base Strength

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