Chemistry Exam 2

Modern Atomic Theory:

3.1 Atomic Theory (Practice problems: 3.1-3.4, 3.36-3.45)

1. All matter is composed of atoms.

2. The atoms of a given element differ from the atoms of element.

3. Chemical compounds consist of atoms combined in specific ratios.

4. Chemical reactions change only the way the atoms are combined in

compounds; the atom themselves are unchanged.

• Atoms are composed of tiny called _____________________, _______________________, and ______________________.

• The masses of atoms and their constituent subatomic particles are very ___________________ when measured in _______________________. Atomic masses are expressed on a _____________________________ scale. One atom is assigned a mass, and all others are measured relative to it.

• The basis for the relative atomic mass scale is an atom of ________________ that contains ______________________ and __________________. This carbon atom is assigned a mass of exactly ______________________________.

• Both protons and neutrons have a mass close to ______________________.

• Electrons are _____________________________ than protons and neutrons.

• Protons and electrons have __________________________________ that are equal in ____________________ but opposite in _____________________.

• The protons and neutrons are packed closely together in a dense core called the ___________________________. Surrounding the nucleus, the electrons move about rapidly through ______________________________________________.

• Diameter of a nucleus is only about ___________________.

• Diameter of an atom is only about ___________________.

• The structure of the atom is determined by interplay of ________________________.

• Opposite electrical charges ___________________ each other, like charges

  _______________________ each other.

• Protons and neutrons in the nucleus are held together by the ______________________.

  3.2 Elements and Atomic Number (Practice problems: 3.5-3.7, 3.46-3.47)

• Atomic Number (Z): The number of _______________________ in each atom of an element. All atoms of a particular element have the same number of _____________________ in the nucleus.

• Atoms are ____________________________ overall and have no ___________________ because the number of positively charged ________________ and the number of negatively charged _________________ are ___________________ in each atom.

• Mass Number (A): The total number of __________________________ in an atom.

  3.3 Isotopes and Atomic Weight (Practice problems: 3.8-3.10, 3.48-3.59)

• Isotopes: Atoms with identical _______________________ but different _______________________ are called __________________. Protium, deuterium, and tritium are three isotopes of the element ___________________________.

– H, most abundant hydrogen isotope has _____________ proton and ___________ neutrons (Z= , A= )

• –  D, this heavy hydrogen isotope has ___________ proton and ______________ neutron (Z= , A= ),

• –  T, this radioactive hydrogen isotope has ____________ proton and _____________ neutrons (Z= , A= ).

• Atomic Weight: The _________________________________ of an element’s atoms in a large sample that includes _________________________________ of that atom.

• –  To calculate the atomic weight of an element, the __________________________ and the ___________________________ of each naturally occurring isotope must be known.

• –  Atomic weight =

  3.4 The Periodic Table (Practice problems: 3.11-3.13, 3.60-3.65)

  ► Elements are arranged by increasing atomic number into horizontal rows, called_____________________________ and vertical columns, called __________________.

• ►  The elements in a given group have similar _______________________________.

• ►  The table has 114 boxes, each of which tells the _________________,

  _____________________, and ________________________ of an element.

• ►  The groups on the periodic table are divided into three main categories.

  ► Main Groups
  ► Transition Metal Groups
  ► Inner Transition Metal Groups

•

•

3.5 Characteristics of Different Groups

(Practice problems: 3.14-3.16, 3.66-3.71) Group 1A or 1 Alkali metals:

•

•

Group 2A or 2 Alkaline earth metals: ► Be,Mg,Ca,Sr,Ba,andRa
► Lustrous, silvery metals
► React with _______

► They are __________ reactive to water than the alkali metals Group 7A or 17 Halogens:

• ►  F, Cl, Br, I, and At

• ►  Colorful and corrosive _____________

• ►  All are found in nature in combination with other elements, such as with sodium in sodium chloride (NaCl)

  Group 8A or 18 Noble gases:
  ► He,Ne,Ar,Kr,Xe,andRn
  ► Colorless ______________
  ► Very _________ chemical reactivity

► ► ►

Li,Na,K,Rb,Cs,andFr
Shiny, soft, and ______ melting point metals

All react rapidly with water to form flammable ___ gas and alkaline or basic solutions

3.6 Electronic Structure of Atoms

(Practice problems: 3.17-3.19, 3.72-3.77)

Quantum mechanical model of atomic structure:

•   The _________________ in an atom are grouped around the nucleus into ___________.

•   The farther a shell is from the nucleus, the ________________ it is, the more

  _____________ it can hold, and the _______________ the energies of those electrons.

•   The _______________ shell closest to the nucleus is labeled shell 1,the next one is shell 2,

  and so on

•   Within the shells, electrons are further grouped into ___________________ of four different types, identified as ________________________ in order of increasing _______________.

•   Different orbitals have different ___________________. Orbitals in s subshells are ________________ , while orbitals in p subshells are roughly ______________ shaped.

•   Any orbital can hold a maximum of ___ electrons.

  3.7 Electron Configurations (Practice problems: 3.20-3.23, 3.78-3.83)

  Electron Configuration: The ___________________________ of electrons in atom’s shells and subshells. Rules to predict electron configuration:

  •   Electrons occupy the ______________________ orbitals available first.

  •   Each orbital can hold only ______________ electrons, which must be of ____________.

  •   If two or more orbitals have the same energy, each orbital gets ___________________ before any orbital gets _______________________.

3.8 Electron Configuration and the

Periodic Table
(Practice problems: 3.24-3.27, 3.84-3.87, 3.112)

•   Valence Shell :

•   Valence electrons: An electron in an ______________________ of an atom. These electrons are ________________________, they are most important in determining an element’s _________________________.

  3.9 Electron-Dot Symbols (Practice problems: 3.28-3.29, 3.88)

  Electron-dot symbol: An atomic symbol with dots placed around it to indicate ___________________________________________________________.

  Examples:

Module 5

Chapter 4: Ionic Compounds Goals

1. What is an ion, what is an ionic bond, and what are the general characteristics of ionic compounds?

2. What is the octet rule, and how does it apply to ions?
   - Predict the electron configurations of ions of main group elements.

3. What is the relationship between an element’s position in the periodic table and the

formation of its ion?

4. What determines the chemical formula of an ionic compound?

   - Write formulas for ionic compounds, given the identities of the ions.

5. How are ionic compounds named?

   - Name an ionic compound from its formula

   - Give the formula of a compound from its name

6. What are acids and bases?

   4.1 Ions
   (Practice problems: 4.1-4.3, 4.38-4.41)

• Atoms are electrically ________________ because the number of __________________ equals the number of _______________________.

• By gaining or losing one or more electrons, however, an atom can be converted into a ________________________ called an __________________.

• The symbol for an ion is written by adding the electrical charge as a ____________________________ to the symbol for the element.

• The ________________ of one or more electrons from a neutral atom gives a _______________________ charged ion called a ___________________.

• The ________________ of one or more electrons by a neutral atom gives a _______________________ charged ion called an ____________________.

  4.2 Periodic Properties and Ion Formation (Practice problems: 4.5-4.6, 4.31-4.35, 4.52-4.59)

• Ionization energy: The energy required to _____________________ from a single atom in the _________________ state.

• Low ionization energies (IE) favor _____________________ formation.

• Electron affinity: The energy released on __________________________ to a single

  atom in the ___________________ state.

• High electron affinities (EA) favor ___________________ formation.

• Going from left to right on the periodic table, IE and EA values both ________________.

• ________________________ have the lowest ionization energies and ___________ an electron most easily.

• ________________________ have the highest electron affinities and ____________ an electron most easily.

• The __________________ neither gain nor lose an electron easily. They have __________ IE values and _____________ EA values.

• Main group elements near the ___________________ of the periodic table have _____________________________ values of both IE and EA.

• These elements near group 4A lack a strong preference to either lose or gain electrons.

• These elements tend not to form ___________________ bonds but form _________________ bonds instead.

  4.3 Ionic Bonds

• In a violent reaction, __________________ atoms transfer electrons to _______________ atoms forming _____________ ions and _______________ ions.

• The opposite electrical charges _____________________ each other. Crystals of sodium chloride held together by _________________________ result that are unlike either of the elements from which they are formed.

• Ionic bond: The _____________________ attractions between ___________________________ in a crystal.

• Ionic compound: A compound that contains ___________________________.

  4.4 Some Properties of Ionic Compounds

• Ionic compounds are usually _____________________ solids.

• Ions in an ionic solid are held ___________________ by attraction to their neighbors and __________________________________.

• Once an ionic solid is dissolved in water or melted, the ions can __________________ and _____________________________.

• High _____________________ and _______________________ are observed for ionic compounds because the attractive forces are _________________________.

• Ionic solids are not _______________________ and will ____________ if struck sharply.

• Ionic compounds __________________ in water if the attraction between water and the ions overcomes the ______________________________________________.

4.5 Ions and the Octet Rule (Practice problems: 4.7-4.9, 4.44-4.47)

► Main group elements often combine in such a way that each winds up with an ____________________________ like a ______________________.

► Octet rule: Main group elements tend to undergo ____________________ that leave them with ___________________________.

4.6 Ions of Some Common Elements (Practice problems: 4.10-4.12, 4.42-4.43, 4.48-4.51)

► Ionic _________________________ of main group elements can be predicted using the _________________________.

4.8 Polyatomic Ions

(Practice problems: 4.16-4.17, 4.60-4.65)

• Ions that are composed of ____________________________ are called polyatomic ions.

• i.e. sulfate ion

4.9 Formulas of Ionic Compounds (Practice problems: 4.18-4.23, 4.36-4.37, 4.66-4.71)

4.10 Naming Ionic Compounds (Practice problems: 4.13-4.15, 4.24-4.28, 4.72-4.77)

4.11 H+ and OH- Ions: An Introduction to

Acids and Bases

(Practice problems: 4.29-4.30, 4.79)
• Acid: A substance that provides __________________ in ______________

– for example:
• Base: A substance that provides __________________ in ______________

– for example:

General Questions and Problems: 4.96, 4.98

Module 6

Chapter 5: Molecular Compounds Goals

1. What is a covalent bond?

2. How does the octet rule apply to covalent bond formation?

3. How are molecular compounds represented?

4. What is the influence of valence-shell electrons on molecular shape?

5. When are bonds and molecules polar?

6. What are the major differences between ionic and molecular compounds?

   5. 1 Covalent Bonds (Practice problems: 5.1, 5.27-5.28)

• The bond formed when atoms ____________________ is called a covalent bond. (Unlike ionic bonds, which involve the ____________________ of electrons).

• A ________________________ held together by covalent bonds is called a _____________________.

• Main group elements can complete their outer subshells by sharing an appropriate number of electrons in covalent bonds.

• If atoms are too far apart, attractions are _______________ and __________________.

• If atoms are too close, strong _______________________ occur.

• When atoms are optimally separated, the energy is at a ________________________.

• The ___________________________ at this minimum energy point is called the bond length.

5.2 Covalent Bonds and the Periodic

Table
(Practice problems: 5.2-5.4)

• In addition to H2 and Cl2, five other elements always exist as _____________________ molecules.

• They are:

• Covalent bonds can form between unlike atoms making possible a vast number of molecular compounds: compounds that consist of ___________________ rather than _______________________.

• H2O NH3 CH4

• The octet “rule” is a useful guideline, but it has numerous ________________________.

• Boron has only ________ valence electrons it can share and thus forms compounds in which it has only _____________________________.

• Elements in the ___________________________ have vacant __________________ that can be used to make more than 4 bonds.

  Examples:

  5.3 Multiple Covalent Bonds

  (Practice problems: 5.5-5.6, 5.31-5.33)

• Sometimes, _______________________ electrons need to be shared

• Single bond - A covalent bond formed by _________________ one electron pair.

• Double bond = sharing _________________________________.

• Triple bond Ξ sharing ________________________________.

• ______________________, _____________________, and _______________ are the elements most often present in multiple bonds.

  5.4 Coordinate Covalent Bonds

• Coordinate covalent bond: The covalent bond that forms when ________________________________________________________________________

• i.e. ammonium ion, transition metals

  5.5 Molecular Formulas and Lewis

  Structures (Practice problems: 5.48, 5.50-5.55)

• Molecular formula: A formula that shows the ___________________and ______________ of atoms in one ____________________ of a compound.

• Structural formula: A molecular representation that shows the ___________________ among atoms by using _______________________ to represent covalent bonds.

• Lewis structure: A molecular representation that shows both the __________________ among atoms and the __________________________________________________.

5.6 Drawing Lewis Structures (Practice problems: 5.7-5.11, 5.59-5.68)

• Certain elements have tendencies/preferences in terms of _________________________________________________.

• _________________________________ help to identify these tendencies

• i.e., H, B, C, N, O, F

• Steps to Drawing a Lewis Structure:

  1. Tally up the _________________________ in the molecule/polyatomic ion

  2. Draw the _________________ with ______________________ bonds based on the ____________________ and/or _________________________

  3. Complete ___________________ with __________________________ 4. Use ___________________________ if necessary
  5.

  5.7 The Shapes of Molecules (Practice problems: 5.12-5.16, 5.29-5.31, 5.69-5.74)

• Molecular shapes can be predicted by applying the______________________________________________________________ model.

• The basic idea of the VSEPR model is that the negatively charged ___________________ in _________________ and ________________________ _______________ each other, and keep as far apart as possible.

  There are three steps to applying the VSEPR model:

• Step 1: Draw a ______________________________ of the molecule

• Step 2: Count the number of _________________________________ surrounding the

  atom of interest.

• Step 3: Predict molecular shape by assuming that the __________________ orient in space so that they are _____________________________________________________.

  Bond Angles

• 2 charge clouds:

• 3 charge clouds:

• 4 charge clouds:

  5.8 Polar Covalent Bonds and

  Electronegativity

  (Practice problems: 5.17-5.19, 5.75-5.82)

• Electrons in a covalent bond occupy the region ______________________________.

• If the atoms are_________________________, as in H2 and Cl2, electrons are attracted ___________________________ to both atoms and are _______________________.

• Polar covalent bond – a bond in which the bonding electrons are ____________________________ by one atom than by the other and thus shared ____________________________.

• When charges __________________________in a neutral molecule, the molecule has a __________________________ and is said to be ____________________.

• In HCl, electrons spend more time near the ______________ than the ______________. Although the molecule is overall __________________, the chlorine is more

____________________ than the hydrogen, resulting in ____________________ on the atoms.

• Partial charges are represented by a ____________ on the more negative atom and ____________ on the more positive atom.

• The ability of an atom to attract electrons________________________ is called the atom’s ____________________________.

• _________________________, the most electronegative element, is assigned a value of 4, and less electronegative atoms assigned lower values.

• Electronegativity is related to _______________________________!

• Elements at the _______________________ of the periodic table are most electronegative, those at the __________________are least electronegative. Noble gases are ____________________________.

• As a rule of thumb, _____________________ differences of _________________ result in ______________________ bonds, differences _____________________ indicate increasingly ___________________ bonds, and differences of ____________________ indicate _________________ bonds.

• There is no sharp dividing line between covalent and ionic bonds!

5.9 Polar Molecules (Practice problems: 5.20-5.22, 5.34, 5.83-5.86)

• Entire molecules can be ___________________ if electrons are attracted more strongly to one ________________ of the molecule than to another.

• Polarity has a dramatic effect on the _____________________________ of molecules, particularly on _____________________, ___________________, and ______________.

• Dipoles or polarity can be represented by an _____________ pointing to the ____________ end of the molecule with a ____________ at the _____________ end

• Just because a molecule has _______________________________ does NOT mean that the molecule is polar overall!

  5.10 Naming Molecular Compounds (Practice problems: 5.23-5.24, 5.87-5.90)