Unit 2: The Atom

Question 1

Democritus

Answer 1

all matter is made of indestructible atoms

Question 2

Dalton

Answer 2

all elements are made of identical atoms and they can combine to make compounds

Question 3

Thomson

Answer 3

● plum-pudding model
● discovered electron

Question 4

Rutherford

Answer 4

positive charged nucleus surrounded by eletrons

Question 5

Bohr

Answer 5

● discovered energy levels
● 2n^2

Question 6

Chadwick

Answer 6

discovered neutron

Question 7

Proton

Answer 7

● Positively Charged
● 1.673*10^-27 kg
● 1 amu (1.0073 amu (atomic mass units))
● In the nucleus

Question 8

Neutron

Answer 8

● Not charged
● 1.675*10^-27 kg
● 1 amu (1.0087 amu)
● In the nucleus

Question 9

Electron

Answer 9

● Negatively charged
● 9.109*10^-31 kg
● 0 amu (0.00055 amu)
● Orbiting the nucleus in specific regions

Question 10

Atomic Structure

Answer 10

● Nucleus
➜ Central region
➜ Very dense
➜ Held together by a “strong force”
● The rest is empty space
● Bee in a cathedral analogy - Nucleus = bee, rest of atom = cathedral

Question 11

Periodic table element (in order going down)

Answer 11

● Atomic # - # of protons
● Element Symbol - 1-2 letters, capitalize first
● Element name
● Average atomic mass

Question 12

Isotopes

Answer 12

● Different atoms of the same element that have different #s of neutrons
● Identified by mass #
● Mass # = # of protons + # of neutrons for an isotope
● DIFFERENT than average atomic mass on periodic table

Question 13

Isotope example: Carbon -13

Answer 13

Mass # - 13 C - Symbol
Atomic # - 6

Question 14

Carbon - 14

Answer 14

Symbol: C - periodic table
Atomic #: 6 - periodic table
Mass #: 14 - given/protons + neutrons
# of protons: 6 - atomic #
# of neutrons: 8 - protons + neutrons = mass #
# of electrons: 6 - electrons = protons in a neutral atom

Question 15

Average atomic mass

Answer 15

● Given on periodic table
● Not a whole # - NOT mass #
● Takes into account the amount of each isotope naturally present

Question 16

Average Atomic Mass formula

Answer 16

● Mass # x (% abundance x 100) = ___ amu
● Add values together from each isotope

Question 17

Which isotope has the greatest abundance: Kr-83 or Kr-84?

Answer 17

Kr-84; the molar mass of Kr (83.796) is closer to 84 than 83.

Question 18

Energy levels

Answer 18

● 1st/most basic level of electron organization
● rings from Bohr model
● numbered 1, 2, 3, etc.
● bigger number = higher energy/farther from nucleus
● “floors”

Question 19

Sublevels

Answer 19

● divisions in energy levels
● s, p, d, f
● E.L. 1 - s
● E.L. 2 - s, p
● E.L. 3 - s, p, d
● E.L. 4 - s, p, d, f

Question 20

Orbitals

Answer 20

● S - 1 orbital
● P - 3 orbitals
● D - 5 orbitals
● F - 7 orbitals
● “rooms”

Question 21

Electron Configuration: Helium

Answer 21

1s^2
● 1 - energy level
● s - sublevel
● 2 - # of electrons in sublevel

Question 22

Pauli exclusion principal

Answer 22

● Only 2 electrons max in each orbital
● Electrons must spin in opposite directions

Question 23

Aufbau Principle

Answer 23

● Fill lowest energy level first
● bau = below

Question 24

Hund’s Rule

Answer 24

● Electrons must fill every orbital in a sublevel before doubling up
● Bus rule

Question 25

Electron configuration exceptions

Answer 25

● Chromium - 1s2 2s2 2p6 3s2 3p6 3d5 4s1 - 4s and 3d are very close in energy, half full is more stable ● Copper - 1s2 2s2 2p6 3s2 3p6 3d10 4s1 - Full 3d is more stable than full 4s

Question 26

Kernel Structure

Answer 26

● Shorthand version of electron configuration

Question 27

Light

Answer 27

● behaves as a particle and a wave - wavelength - frequency ● Wavelength and frequency are inversely proportional ● Energy and wavelength are directly proportional

Question 28

Heisenberg Uncertainty Principle

Answer 28

● orbital "blur" is the closest to finding electrons ● it is impossible to know the exact location and velocity of a particle at the same time ● observe electrons with light ● electrons absorb light (energy) ● electron's velocity changes

Question 29

Match the colors with the wavelength, frequency, and energy

Answer 29

violet - short wavelength, high frequency, high energy red - long wavelength, low frequency, low energy

Question 30

Absorption

Answer 30

● electrons absorb energy from the electromagnetic spectrum ● allows them to jump to a higher energy level ● "excited" state ● farther from the nucleus ● black bars

Question 31

Emission

Answer 31

● electrons release the energy as light ● "ground" state ● closer to the nucleus ● colored bars

Question 32

Why are colors produced?

Answer 32

● When electrons return to their ground state, they emit energy equivalent to the energy of the colors they emit ● High - purple, low - red

Question 33

Mendeleev

Answer 33

● organized periodic table ● noticed patterns

Question 34

Metals

Answer 34

● Usually solids at room temp ● shiny ● ductile/malleable ● good conductors

Question 35

Non-metals

Answer 35

● solid, liquid, or gas at room temp ● brittle ● poor conductors ● hydrogen

Question 36

Metalloids

Answer 36

● boron, silicon, germanium, arsenic, antimony, tellurium, polonium, astatine ● touches zigzag ● properties of both ● semiconductors with other elements

Question 37

Periodic table sections

Answer 37

● Main group elements - s and p block ● Transition metals - d block ● Inner transition metals - f block ● Alkali metals - column 1 ● Alkaline Earth Metals - column 2 ● Halogens - column 17 (-tennessine) ● Noble gases - last column

Question 38

Coulombic attraction

Answer 38

force of attraction between positive and negative charges

Question 39

Effective nuclear charge

Answer 39

● A measure of how much positive pull of the nucleus an electron feels ● Increases across the rows of the periodic table - more protons = more pull

Question 40

Electron shielding

Answer 40

● Electrons in higher energy levels feel less of a pull from the nucleus - farther away - repelled by inner electrons - "shielded" by inner electrons ● Increases down the columns of the periodic table as atoms have more electrons/energy levels

Question 41

Atomic radius

Answer 41

● Radius (nucleus to outer edge of last energy level) ● Increases down a column (more energy levels, less pull) ● Decreases across a row (increase in protons attracts electrons closer to the nucleus)

Question 42

First Ionization Energy

Answer 42

● Energy needed to remove 1 electron ● Decreases down a column (electron shielding = less attraction = less energy to go against) ● Increases across a row (# of protons increases, harder to remove electrons) ● Matches with electronegativity

Question 43

Electrogativity

Answer 43

● Measure of how "greedy" an atom is for electrons in a chemical bond ● Decreases down a column (more electron shielding = nucleus has less force) ● Increases across a row (effective nuclear charge = more attraction to electrons)