Atoms and the Periodic Table

Question 1

Law of Conservation of Mass

Answer 1

during chemical reactions, matter is neither created nor destroyed

Question 2

Law of Definite Proportions

Answer 2

any given compound is composed of definite proportions by mass of its elements

Question 3

proportion by mass

Answer 3

the ratio of the mass of the element to the total mass of the compound

Question 4

percent by mass

Answer 4

proportion of the element multiplied by 100%

Question 5

A 4.33 g sample of dinitrogen monoxide, N2O, is composed of 63.65% nitrogen and 36.35% oxygen by mass. What is the percent composition of a 14.9 g sample of N2O?

Answer 5

All pure samples of N2O have the same percent composition: 63.65% nitrogen and 36.35% oxygen by mass.

Question 6

Calculate the mass of nitrogen in a 4.75 g sample of nitrogen monoxide, NO, which has a percent composition of 46.68% nitrogen and 53.32% oxygen by mass.

Answer 6

mass of N = 46.68%/100%(4.75 g) = 2.22 g N

Question 7

Law of Multiple Proportions

Answer 7

for any two (or more) compounds that are composed of the same elements, for a given mass of one of the elements, the ratio of the masses of any other element in the compounds is a small, whole-number ratio

Question 8

Subatomic partcles

Answer 8

neutrons, protons, and electrons

Question 9

the atomic nucleus is incredibly tiny, but contains almost all the mass of the atom

Answer 9

true

Question 10

electrons have very little mass, but occupy almost all the volume of the atom

Answer 10

true

Question 11

Proton

Answer 11

Charge = +1, located in the nucleus

Question 12

Neutron

Answer 12

Neutral charge, located in the nucleus

Question 13

Electron

Answer 13

Charge = -1, located outside of the nucleus

Question 14

Atomic Number, Z

Answer 14

The number of protons in an atom’s nucleus; determines the atom’s identitiy

Question 15

Isotope

Answer 15

two atoms with the same number of protons but different numbers of neutrons

Question 16

Ions

Answer 16

charged particles

Question 17

cation

Answer 17

positive ion (lost an electron)

Question 18

anion

Answer 18

negative ion (gained an electron)

Question 19

Calculation of Atomic Mass

Answer 19

∑(𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑖𝑠𝑜𝑡𝑜𝑝𝑒×𝑚𝑎𝑠𝑠 𝑜𝑓 𝑖𝑠𝑜𝑡𝑜𝑝𝑒)

Question 20

Naturally occurring copper consists of 69.17%63Cu, which has an isotope mass of 62.9396 u, and 30.83%65Cu, which has an isotope mass of 64.9278 u. What is the atomic mass of copper?

Answer 20

(0.6917)(62.9396 𝑢)+(0.3083)(64.9278 𝑢)=63.55 𝑢

Question 21

Two pairs of elements that are out of place according to atomic mass

Answer 21

argon/potassium
cobalt/nickel

Question 22

Noble Gases

Answer 22

8A; He, Ne, Ar, Kr, Xe, Rn; balanced

Question 23

Alkali Metals

Answer 23

1A; H, Li, Na, K, Rb, Cs, Fr; charge of +1

Question 24

Alkaline Earth metals

Answer 24

2A; Be, Mg, Ca, Sr, Ba, Ra; Charge of +2

Question 24

Coinage Metals

Answer 24

1B, 11; Cu, Ag, Au; Positive charge

Question 25

Halogens

Answer 25

7A; F, Cl, Br, I, At; Charge of -1

Question 26

Properties of Metals

Answer 26

shiny, malleable/ductile, conductors of heat and electricity

Question 27

Properties of nonmetals

Answer 27

brittle (as solids)

Question 28

Metalloids

Answer 28

share properties with both metals and nonmetals