Unit 1

Question 1

Atomos

Answer 1

Word, meaning indivisible, used to describe matter by Greek Philosophers around 400 BCE.

Question 2

John Dalton

Answer 2

Proposed first atomic theory.

• All matter made up of atoms
• All atoms of an element are identical
• Atoms of different elements differ
• Atoms are rearranged to form new substances
• Matter is neither created nor destroyed

Question 3

J.J Thomson

Answer 3

Discovered the electron. Proposed plum pudding model of the atom.

Question 4

Ernest Rutherford

Answer 4

Performed gold foil experiment to discover the nucleus. Also discovered that electrons were outside the nucleus.

Question 5

Niels Bohr

Answer 5

Proposed that electrons rested on energy levels which were explained by the atomic spectrum.

Question 6

James Chadwick

Answer 6

Discovered the neutron, a particle with no mass or charge.

Question 7

Isotopes

Answer 7

A form of an element where the atoms have he same number of protons as all other forms but a different number of neutrons.

Question 8

Atomic Mass

Answer 8

The weighted average of the masses of all the naturally occurring isotopes of an element.

Question 9

Periodic Law

Answer 9

Properties of elements repeat when elements are arranged by increasing atomic number.

Question 10

Atomic Radius

Answer 10

A measurement of the size of an atom.

Question 11

Effective Nuclear Charge

Answer 11

The net force experienced by an electron in an atom due to the positively charged nucleus.

Question 12

Ionic Radius

Answer 12

A measurement of the size of an atom.

Question 13

Cations are ________ than their neutral atoms because they have lost electrons.

Answer 13

smaller

Question 14

Anions are ________ than their neutral atoms because they have gained electrons.

Answer 14

larger

Question 15

Ionization Energy

Answer 15

The quantity of energy required to remove an electron from an atom or ion; measured in kilojoules per mole.

Question 16

Electron Affinity

Answer 16

The energy change that occurs when an electron is added to a neutral atom; measured in kilojoules per mole.

Question 17

Electronegativity

Answer 17

The ability of an atom to attract bonding electrons to itself.

Question 18

Ionic compounds occur between…

Answer 18

A metal and a nonmetal.

Question 19

Characteristics of ionic compounds.

Answer 19

• hard and brittle
• high melting and boiling points
• conduct electricity as liquids or solutions
• form a crystal lattice as solids

Question 20

Electrolyte

Answer 20

A compound that conducts electricity when dissolved in water.

Question 21

Molecular/Covalent Compounds

Answer 21

Consist of two nonmetals.

Question 22

Characteristics of molecular/covalent compounds.

Answer 22

• soft
• low melting and boiling points
• don’t conduct electricity
• form discreet molecules

Question 23

Formation of molecular/covalent compounds.

H & halogens need ___ bond
O needs ___ bonds
N needs ___ bonds
C needs ___ bonds

Answer 23

1
2
3
4

Question 24

E.N.D = 0

Answer 24

Non-polar/ pure covalent bond.

Question 25

E.N.D is between 0 and 1.7

Answer 25

Polar covalent bond.

Question 26

E.N.D is greater than 1.7

Answer 26

Ionic bond.

Question 27

London Dispersion Forces

Answer 27

Occur between non-polar molecules. At any given moment, electrons will disperse more to one side of a molecule.

Question 28

Dipole-Dipole Forces

Answer 28

Occur between polar molecules.

Question 29

Hydrogen Bonding

Answer 29

Strongest IMF. Occurs between polar molecules that have H-F, H-O, and H-N bonds.

Question 30

Hydrogen bonding accounts for what weird properties of water?

Answer 30

- Surface tension - Ice less dense than water - High heat capacity - High melting and boiling points