Atomic Theory

Question 0

J.J. Thomson

Answer 0

cathode ray experiments, discovered electrons, plum pudding model

Question 1

John Dalton

Answer 1

all matter is made of atoms, elements have atoms that combine to form compounds, atoms are rearranged in reactions

Question 2

Rutherford

Answer 2

gold foil experiment (some light rays reflected), discovered nucleus (positively charged center with protons), electrons orbit nucleus like planets

Question 3

Neils Bohr

Answer 3

energy levels, electrons move in shells around nucleus

Question 4

Chadwick

Answer 4

discovered neutron

Question 5

Schrödinger/Heisenberg

Answer 5

electrons in cloud, not visible orbits, particles behave like waves

Question 6

c=fw

Answer 6

speed of light=frequency x wavelength

Question 7

c

Answer 7

speed of light: 3.0x10^8 m/s

Question 8

energy equation

Answer 8

E=hf

energy=plank’s constant x frequency

Question 9

Plank’s constant

Answer 9

h=6.63x10^-34

Question 10

effective nuclear charge

Answer 10

actual pull on the electron from the nucleus

Question 11

Effective nuclear charge equation

Answer 11

Zeff=Z-S

effective nuclear charge=protons-core electrons

Question 12

atomic radius

Answer 12

distance between 2 atoms center to center

Question 13

rules for atomic radius

Answer 13

1. increases as you add energy levels (down)
2. increases as you decrease effective nuclear charge (left)
   - less pull on the electrons=more spread out

Question 14

rules for ionic size

Answer 14

1. more electrons=more orbitals and bigger electron cloud (down)
2. cations are smaller when charged
3. anions are bigger when charged

Question 15

ionization energy

Answer 15

amount of energy required to remove an electron from ground state of a gaseous atom/ion

Question 16

rules for ionization energy

Answer 16

1. increases as effective nuclear charge increases (right)
   - more core electrons=harder to remove
2. increases as energy levels/orbitals decrease (up)
   - easier to remove electrons when they are more spread out

Question 17

exceptions to ionization energy rules

Answer 17

don’t increase as you go right

1. 2A–> 3A (p and s orbitals of 2A are more shielded)
2. 5A–> 6A (electrons in p orbital of 6A are paired to they repel each other a little)

Question 18

Lewis Dot diagram

Answer 18

symbol: nucleus and core electrons
dots: valence electrons

Question 19

rules for paramagnetic attraction

Answer 19

using Hund’s rule:

1. if unpaired electrons, then paramagnetic
2. if all electrons paired, diamagnetic
3. paramagnetic elements are more paramagnetic if they have more unpaired electrons