CH 3

Question 1

atom

Answer 1

smallest particle of an element that retains its chemical identity after a chemical reaction

Question 2

democritius believed

Answer 2

indivisible and indestructible

Question 3

democritius’s ideas were limited because

Answer 3

they didn’t explain chemical behavior and they lacked experimental support

Question 4

dalton’s atomic theory

Answer 4

all elements are made of atoms
atoms of the same element are identical
atoms of one element are different than any other element
atoms of different elements can physically mix or chemically combine in whole number ratios
atoms of one element are never changed into atoms of another element

Question 5

electrons

Answer 5

negative charge, outside nucleus

Question 6

who discovered electrons

Answer 6

jj thomson using cathode ray

Question 7

who discovered protons

Answer 7

eugene goldstein using the cathode ray

Question 8

who discovered the neutron

Answer 8

james chadwick

Question 9

which subatomic particle has the least mass

Answer 9

electron

Question 10

plum pudding model

Answer 10

atoms filled with positively charged material and electrons distributed throughout

Question 11

rutherfurd’s gold foil experiment

Answer 11

directed narrow beam of alpha particles at a thin sheet of gold foil, most went through but some were deflected
atom mostly empty space
all mass concentrated in the nucleus

Question 12

nucleus

Answer 12

contains protons and neutrons

Question 13

what is the charge of an alpha particle

Answer 13

positive

Question 14

what is the charge of the nueleus

Answer 14

positive

Question 15

protons and ____ are equal

Answer 15

electrons. protons = electrons

Question 16

atomic mass

Answer 16

protons + neutrons

Question 17

atomic number

Answer 17

number of protons

Question 18

the type of element is determined by the

Answer 18

number of protons

Question 19

number of neutrons

Answer 19

mass number - atomic number

Question 20

isotope

Answer 20

atoms that have the same number of protons but differnt number of neutrons (different mass numbers)

Question 21

how do you calculate the atomic mass of an element

Answer 21

average of all of the isotopes

Question 22

atomic mass

Answer 22

mass and relative abundance of the isotopes as they occur in nature

Question 23

calculate atomic mass

Answer 23

mutiply the mass of each isotope by its natural abudance, expressed as a deical, then add te products

Question 24

families

Answer 24

colums

Question 25

periods

Answer 25

rows