AP Chem Ch1

Question 1

Law of composition (law of definite proportion)

Answer 1

A pure compound will always have the same proportion of the same elements. So salt (NaCl) contains the same proportions of the elements sodium and chlorine no matter how much salt you have or where the salt came from.

Question 2

Photoelectric effect

Answer 2

The emission of electrons or other free carriers when light shines on a material.

Question 3

What is the wave particle duality and where does it apply?

Answer 3

XXX

Question 4

Shape of p-orbital

Answer 4

Dumbells.

Question 5

What was used to determine the charge of the electron?

Answer 5

Oil drop experiment (electrically charged oil drops were suspended using charge. Using knowledge of the force of gravity, the force of electric charge could be deduced).

Question 6

Dalton’s theory

Answer 6

1: All matter is made of atoms, which are indivisible.
2: All atoms of a given element are identical in mass and properties.
3: A chemical reaction is a rearrangement of atoms.

Question 7

What do the different quantum number describe?

Answer 7

1. n - Principal energy level. Integer starting at 1. Represents the average distance of the electron from the nucleus, or the size of the principle energy level.
2. l - Azimuthal quantum number. The sublevel. A sublevel corresponds to a orbital shape/type (s,p,d,f…).
3. ml - Magnetic quantum number. A number given to each orbital in a sublevel. Ranges from -l to +l. Represents the orientation of the orbital.
4. ms - spin quantum number. My be either +1/2 or -1/2. Represents the spin of the electron

Question 8

Law of multiple proportions

Answer 8

If you have two compounds, both with elements A and B. (NO and NO2 e.g.), if you have a fixed amount of nitrogen, the oxygen will be proportional.

Question 9

Plum pudding model of the atom

Answer 9

Early 20th century model of the atom where electrons bathed in a sea of positive charges.

Question 10

What did the cathode ray tube experiment discover (what, who, and when)?

Answer 10

Sir William Crookes in 1870 used it to discover cathode rays. Later, J.J. Thomas in 1897 determined that cathode rays were a fundamental part of matter called electrons. He used the CRT to the charge to mass ratio.

Question 11

What did the gold foil experiment show?

Answer 11

The nuclear model of the atom as opposed to the “plum pudding” model.

Question 12

Are electrons particles?

Answer 12

They are but can act as a wave according to the wave-mechanical theory.

Question 13

Heisenberg uncertainty principle

Answer 13

A particle’s position and momentum cannot be precisely known at once.

Question 14

Ground state

Answer 14

The lowest possible energy state for a given atom.

Question 15

Excited state

Answer 15

When an atom has more energy then when it’s in its ground state.

Question 16

Does the wave-mechanical model contradict Bohr’s model?

Answer 16

It specifies - what bohr found about energy emission as electrons move up and down shells is true. And the radius of the electron is correct for hydrogen in both models.

Question 17

Number of sublevels

Answer 17

Principle level ‘n’ has ‘n’ sublevels

Question 18

How many electrons can an orbital hold?

Answer 18

2

Question 19

Number of orbitals

Answer 19

2l + 1

Question 20

Shape of s orbital

Answer 20

Donut

Question 21

Shape of d orbital

Answer 21

Clover (except for the +2 which is like a dumb-bell with a donut around it).

Question 22

Valence electrons

Answer 22

s orbital and p orbital electrons of the outermost shell.

Question 23

For orbital diagrams, what do the blocks represent? What do cells represent?

Answer 23

A block corresponds to a sublevel (l). A cell corresponds to an orbital in that sublevel.

Question 24

Hund’s rule

Answer 24

For a given sublevel, all orbitals get one electron before getting a second.

Question 25

Orbital diagram

Answer 25

The blocks with cells and arrows.

Question 26

Aufbau order and what major elements violate it.

Answer 26

The standard order of electron population (therefore orbital energy levels). Common violators include: Gold, silver, chromium, copper, and molybdenum.

Question 27

Pauli exclusion principle

Answer 27

No two electrons in the same atom may have the same four quantum numbers.