Unit 2: Atoms and Molecules

Question 1

basic particle of chemical elements

Answer 1

atom

Question 2

consists of a nucleus protons and neutrons, surrounded by an
electromagnetically-bound swarm of electrons.

Answer 2

atom

Question 3

nucleus is made up of

Answer 3

proton + neutron

Question 4

subatomic particles of an atom

Answer 4

protons
neutrons
electrons

Question 5

atomic model and theory timeline

Answer 5

democritus
john dalton
jj thomson
ernest rutherford
niels bohr
erwin schrodinger
james chadwick
modern

Question 6

• matter was made of small, hard particles called atoms (atomos)
• indivisible
• proposed that matter could not be divided into smaller pieces forever

Answer 6

democritus

Question 7

• created the very first atomic theory known as the Billiard Bell
• viewed atoms as tiny, solid balls
• matter is made up of atoms
• elements are composed of subatomic atoms
• isotopes, isobars
• compounds are formed from 2 diff elementd
• atoms combine in somple ratios to form compounds

Answer 7

john dalton

Question 8

• raisin bread model/plum pudding
• he showed that the atom was made of even smaller things
• discovered Electrons (with Cathode Ray Tube)

Answer 8

jj thomson

Question 9

• discovered protons gold foil or alpha scattering experiment by using radium
• discovered protons and the nucleus
• he discovered that atoms have (+) particles in the center, and are mostly empty space

Answer 9

ernest rutherford

Question 10

• planetary model
• nucleus is = to protons + neutrons
• nucleus is surrounded by electrons
• improved on rutherford’s model
• proposed that electrons move around the nucleus in specific layers, or shells

Answer 10

niels bohr

Question 11

• quantum mechanical model
• electron cloud model
• estimates the probability of finding an electron in a certain
  position

Answer 11

erwin schrodinger

Question 12

• discovered neturons
• working with rutherford, he discovered particles with no charge, these were called as neutrons

Answer 12

james chadwick

Question 13

• work done since 1920 has changed the model
• the new atomic model has electrons moving around the nucleus in a cloud

Answer 13

modern

Question 14

atomic #

Answer 14

protons = electrons

Question 15

mass #

Answer 15

electrons + neutrons
protons + neutrons

Question 16

neutrons

Answer 16

mass # - electrons
mass # - atomic #

Question 17

• same atomic # but different mass #
• same no. of protons
• H, protium, deuterium, tritium

H1, H2, H3

Answer 17

isotope

Question 18

• same mass # but different elements

calcium (40) and argon (40)

Answer 18

isobar

Question 19

• same # of neutrons
• different elements

carbon 13
nitrogen 14

Answer 19

isotones

Question 20

determines the charge number of an atom, it also tells us the number of electrons in a neutral atom

Answer 20

atomic number

Question 21

The sum of the number of protons and neutrons in an atom (whole number)

Answer 21

mass number

Question 22

The ________ number of protons and neutrons for all natural _________ of an element (decimal number)

Answer 22

atomic mass/weight