Chemistry Midterm

Question 1

What are the atomic number and the atomic mass of potassium?

Answer 1

Atomic #: 19
Atomic Mass: 39

Question 2

Describe the location of metals, nonmetals, metalloids, and noble gases on the periodic table.

Answer 2

the metals are to the left of the line (except for hydrogen, which is a nonmetal), the nonmetals are to the right of the line, and the elements immediately adjacent to line are metalloids.

Question 3

state four indicators of a chemical change.

Answer 3

change of color, production of an odor, change of temperature, evolution of a gas.

Question 4

state two examples of a chemical change

Answer 4

iron rusting, wood burning.

Question 5

what is a physical change?

Answer 5

a physical change is usually reversible change in the physical properties of a substance, as size or shape.

Question 6

state two examples of physical change.

Answer 6

boiling water, crushing a can.

Question 7

are most of the elements on the periodic table metals, metalloids, or nonmetals

Answer 7

most elements are metals.

Question 8

what is chemistry

Answer 8

the branch of science that deals with the identification of the substances of which matter is composed.

Question 9

what is the SI unit for Length?

Answer 9

Meter (m)

Question 10

what is the SI unit for mass?

Answer 10

kilogram (kg)

Question 11

what is the SI unit for time?

Answer 11

seconds (s)

Question 12

what is the SI unit for volume?

Answer 12

cubic meters

Question 13

what is the SI unit for number of particles?

Answer 13

mold

Question 14

state two characteristics of halogens.

Answer 14

form acids when combined with hydrogen, fairly toxic

Question 15

state two characteristics of noble gases.

Answer 15

colorless, odorless

Question 16

state two characteristics of alkali metals

Answer 16

silver-like luster, high ductility.

Question 17

state two characteristics of alkaline earth metals.

Answer 17

good conductors of electricity, low in ionization energy.

Question 18

state two characteristics of Transition metals

Answer 18

good conductors of heat and electricity, can be hammered or bent into shape easily.

Question 19

what is the formula for density?

Answer 19

P = m/v

Question 20

state three characteristics of solids.

Answer 20

definite shape, definite volume, particles vibrate around fixed axes.

Question 21

state three characteristics of liquids

Answer 21

definite volume, no definite shape, possesses only one free surface.

Question 22

state three characteristics of gases.

Answer 22

easy to compress, expand to fill their containers, tends to flow.

Question 23

heterogeneous mixture

Answer 23

one that does not have a uniform composition and in which the individual substances remain distinct.

Question 24

homogeneous mixture

Answer 24

one that has uniform composition throughout and always has a single phase; also called a solution.

Question 25

who wrote the atomic theory?

Answer 25

John Dalton

Question 26

state the atomic theory.

Answer 26

all matter is composed of atoms.

Question 27

state the Law of Multiple Proportions

Answer 27

states that when different compounds are formed by the combination of the same elements, different masses of one element combine with the same fixed mass of the other element in a ration of small whole numbers

Question 28

state the Law of Conservation of Mass

Answer 28

states that mass is neither created nor destroyed during a chemical reaction but is conserved

Question 29

state the Law of Definite Proportions

Answer 29

states that, regardless of the amount, a compound is always composed of the same elements in the same proportions by mass.

Question 30

who conducted the gold foil experiment and what did it prove?

Answer 30

Rutherford’s gold foil experiment showed that the tom is mostly empty space with a tiny, dense, positively charged nucleus.

Question 31

what experiment led to the discovery of the electron.

Answer 31

the cathode ray experiment

Question 32

Describe Millikan’s experiment and what it proved.

Answer 32

Millikan could calculate the charge on the drop, the charges on the drops were all integer multiples of a fundamental unit of charge.

Question 33

most of the mass of an atom is located in the

Answer 33

nucleus

Question 34

most of the volume of the atoms created by the

Answer 34

free space

Question 35

Hund’s rule

Answer 35

states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals.

Question 36

Aufbau’s Principle

Answer 36

states that each electron occupies the lowest energy orbital available

Question 37

Pauli’s Exclusion Principle

Answer 37

states that maximum of two electrons can occupy a single atomic orbital but only if the electrons have opposite spins.

Question 38

why does an electron go from its ground state to its excited state?

Answer 38

if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.

Question 39

how many electrons can the first energy level hold?

Answer 39

2 electrons

Question 40

how many electrons can the second energy level hold?

Answer 40

8 electrons

Question 41

how many electrons can the third energy level hold?

Answer 41

32 electrons

Question 42

ow did Mendeleev and Moseley organize the periodic table differently?

Answer 42

Mendeleev arranged elements ascendingly according to atomic masses, while Moseley` arranged them ascendingly according to atomic number.

Question 43

what is the most electronegative element?

Answer 43

Fluorine

Question 44

Which three elements are most likely to form a double or triple bond?

Answer 44

transition metals Ex: nitrogen

Question 45

state three characteristics of ionic compounds.

Answer 45

have high melting points, hard and brittle, and dissociate into ions when dissolved in water.