Unit 1 - Matter, Chemical Trends & Chemical Bonding

Question 0

What is electron affinity?

Answer 0

The amount of energy released when an electron is added to an atom in the gaseous state; atoms with high electron affinity will release a lot of energy to gain electrons

Question 1

What is ionization energy?

Answer 1

The amount of energy required to remove an electron from an atom in the gaseous state; atoms with low ionization energy easily lose electrons

Question 2

What’s the difference between electron shells closer to the nucleus and shells further away from the nucleus?

Answer 2

Shells closer to the nucleus contain less energy, so more energy must be given off when an electron is added.

Question 3

Valence Shell Electron Pair Repulsion Theory (VSEPR)

Answer 3

The shape of molecules are based on the tendency of electrons to repel one another, since electron clouds want to be the furthest possible distance from other clouds.

Question 4

3 types of van der Waals (intermolecular) forces

Answer 4

1. dipole-dipole
2. (London) dispersion forces
3. hydrogen bonds

Question 5

empirical knowledge vs. theoretical knowledge

Answer 5

Empirical knowledge comes directly from observations, while theoretical knowledge is based on ideas created to explain observations.

Question 6

What is the law of conservation of mass?

Answer 6

law stating that during a chemical reaction matter is neither created nor destroyed; mass of reactants = mass of products

Question 7

What is the law of constant composition?

Answer 7

law stating that compounds always have the same percentage composition by mass

Question 8

Define electronegativity.

Answer 8

Electronegativity is a number that measures the relative ability of an atom to attract bonding electrons.

Question 9

Properties of ionic compounds

Answer 9

• solids at SATP
• electrolytes
• high melting points
• hard, brittle

Question 10

Properties of molecular compounds

Answer 10

• nonelectrolytes
• low melting points
• soft, malleable, flexible

Question 11

Define binary compound.

Answer 11

a compound composed of two kinds of atoms or two kinds of monatomic ions (ions consisting of one charged ion)

Question 12

Define oxyanion.

Answer 12

A polyatomic ion containing oxygen (e.g. ClO3, SO4)

Question 13

What is a polar covalent bond?

Answer 13

A covalent bond formed between atoms with significantly different electronegativities; a bond with some ionic characters

Question 14

What was the gold foil experiment?

Answer 14

An experiment conducted by Rutherford, which involved shooting alpha particles through very thin pieces of gold foil. He found that some particles reflected instead of passing through. This lead to the discovery of the nucleus.

Question 15

Define transition and ground state.

Answer 15

Transition - movement of an electron from one energy level to another
Ground state - the lowest energy level that an electron can occupy

Question 16

What is the bonding capacity?

Answer 16

It is the number of electrons that are NOT part of a lone pair (imagine Lewis diagrams)

Question 17

What is an isotope?

Answer 17

Atoms of an element with a different number of neutrons.

Question 18

Properties of metals

Answer 18

• solids at SATP
• malleable
• ductile
• conductors of electricity
• lustrous

Question 19

Properties of nonmetals

Answer 19

• generally nonconductors of electricity
• brittle
• gases or solids at SATP

Question 20

Difference between intermolecular forces and intramolecular forces

Answer 20

Intermolecular forces are forces between molecules while intramolecular forces are forces between the atoms and ions WITHIN a molecule

Question 21

State the electron capacity of s, p, d, and f subshells.

Answer 21

s orbitals can hold 2 electrons
p orbitals hold 6 electrons
d orbitals hold 10 electrons
f orbitals hold 14 electrons

Question 22

What are electronegativity trends and why?

Answer 22

Electronegativity decreases as you move down the periodic table, because there are more shells between valence electrons and the positive nucleus and atomic radius increases(attraction is less).
It increases as you move left to right because the # of shells stay the same, but there are more protons to attract electrons.

Question 23

What are ionization energy trends and why?

Answer 23

Ionization energy increases as you move up the periodic table, because the effective nuclear charge increases, therefore it takes more energy to remove the electrons.
Generally, it increases as you move left to right, since metals generally want to lose electrons and nonmetals generally want to gain electrons (e.g. alkali metals on the left really want to lose one electron to become stable while noble gases on the right really want to keep electrons)

Question 24

What are electron affinity trends and why?

Answer 24

Electron affinity increases as you move up the periodic table and increases as you move left to right.

Question 25

What are the periodic trends for metals?

Answer 25

Increases as you go down, because valence electrons are more easily given away.
Decreases left to right, because there are more electrons it needs to give away

Question 26

What are the periodic trends for nonmetals?

Answer 26

Reactivity increases as you go up, since valence shells are closer to the nucleus, making it easier to gain electrons
Reactivity increases across a row, since fewer valence electrons are required to make a stable octet

Question 27

List the intermolecular forces in order of strongest to weakest.

Answer 27

1. Hydrogen bonds
2. Dipole-dipole
3. London dispersion

Question 28

What are ionic radius trends and why?

Answer 28

Since nonmetals gain electrons their ionic radius increases with more shells.
Since metals lose electrons, their ionic radius decreases with less shells