Unit 3 Test

What is Coulombic attraction

Electrostatic attraction between positive nucleus and negative electrons strength depends on charge and distance

How distance affects attraction

Greater distance means weaker attraction proportional to 1 over r squared

How nuclear charge affects attraction

More protons means stronger pull on electrons

Coulombic model short rule

Closer and more protons equals stronger attraction

Symbol for wavelength and common units

Lowercase lambda in meters or nanometers

Symbol for frequency and unit

Greek nu in per second or Hertz

If wavelength decreases what happens to frequency

Frequency increases

If wavelength decreases what happens to energy

Energy increases

Convert nanometers to meters

Multiply by 1e-9

Color with longest wavelength

Red

Color with shortest wavelength

Violet

Color with highest photon energy

Violet

Color with lowest photon energy

Red

Why hydrogen gives lines not a continuous band

Energies are quantized so only certain jumps emit specific wavelengths

Why one H atom cannot emit all four lines at once

Only one electron transition occurs at a time

Scientist Planck main idea

Energy is quantized in discrete packets called quanta

Scientist Bohr main idea

Electrons occupy fixed energy levels and emit light when they fall to lower levels

Scientist de Broglie main idea

Matter has wave properties with lambda equals h over p

Scientist Heisenberg main idea

Uncertainty principle delta x times delta p is greater or equal to h over 4 pi

Scientist Schrodinger main idea

Wave equation gives orbitals as probability clouds

Scientist Einstein photoelectric result

Light energy comes in photons E equals h nu which eject electrons above a threshold

Pauli exclusion principle

No two electrons in an atom have the same four quantum numbers and max two electrons per orbital with opposite spins

Hund rule

Electrons occupy degenerate orbitals singly with parallel spins before pairing

Aufbau principle

Electrons fill the lowest energy sublevels first

Order of sublevels by count s p d f

One three five seven orbitals respectively

Max electrons in s p d f

Two six ten fourteen respectively

Energy level to orbital capacity

Level n holds 2n^2 electrons

Atomic radius definition

Size of atom from nucleus to valence electrons

Atomic radius trend across a period

Decreases left to right due to increasing effective nuclear charge

Atomic radius trend down a group

Increases top to bottom due to added energy levels and more shielding

First ionization energy definition

Energy required to remove one electron from a neutral atom in gas phase

First ionization energy trend across a period

Increases left to right as effective nuclear charge strengthens

First ionization energy trend down a group

Decreases top to bottom because valence electrons are farther and more shielded

Electronegativity definition

Relative ability of an atom to attract bonding electrons

Electronegativity trend across a period

Increases left to right with growing effective nuclear charge

Electronegativity trend down a group

Decreases top to bottom as distance and shielding increase

Electron affinity definition

Energy change when a gaseous atom gains an electron more negative means stronger attraction

Electron affinity trend across a period

Becomes more negative overall with irregularities

Electron affinity trend down a group

Becomes less negative overall with irregularities

Metallic character definition

Tendency to lose electrons and show metal properties

Metallic character trend across a period

Decreases from left to right

Metallic character trend down a group

Increases from top to bottom

Shielding effect definition

Repulsion by inner electrons that reduces nuclear pull on valence electrons

Shielding effect trend across a period

Approximately constant within a shell

Shielding effect trend down a group

Increases as layers of inner electrons are added

Cations vs anions size

Cations are smaller than parent atoms and anions are larger than parent atoms

Successive ionization energy jump meaning

Large jump shows removal from a new lower shell so that is the valence electron count in the neutral atom

Electron configuration block order shortcut

Use periodic table blocks to track filling s then p then d then f

Transition metals lose which electrons first

Lose s electrons before d electrons

Ground state exceptions to simple filling

Chromium is [Ar] 4s1 3d5 and Copper is [Ar] 4s1 3d10

Shorthand example K and K plus

K is [Ar] 4s1 and K plus is [Ar]

Shorthand example F and F minus

F is [He] 2s2 2p5 and F minus is [Ne]

Nickel neutral configuration

Ni is [Ar] 4s2 3d8

Nickel two plus configuration

Ni2 plus is [Ar] 3d8

Iron three plus configuration

Fe3 plus is [Ar] 3d5

Copper two plus configuration

Cu2 plus is [Ar] 3d9

Zinc two plus configuration

Zn2 plus is [Ar] 3d10

Color note from electron configuration lab

Transition metal ions with partially filled d sublevels are colored while d0 or d10 ions are usually colorless

Which ions in the lab are colored

Fe3 plus Ni2 plus Cu2 plus are colored

Observed lab colors quick check

Fe3 plus orange Ni2 plus greenish teal Cu2 plus aquamarine

Which ions in the lab are colorless

Na plus Al3 plus Ca2 plus Mg2 plus Ag plus Zn2 plus were clear in solution

Why Zn2 plus is colorless

Zn2 plus has full 3d10 so no d to d transitions

Practice choose larger atomic radius Na vs K

K is larger

Practice choose larger first IE Na vs K

Na has higher first ionization energy

Practice choose higher EN C vs F

F has higher electronegativity

Practice order by increasing atomic radius across period Na Mg Al Si P S Cl Ar

Ar Cl S P Si Al Mg Na

Practice order by increasing first ionization energy Na Mg Al Si P S Cl Ar

Na Mg Al Si P S Cl Ar

Practice ionic size Fe2 plus vs Fe3 plus

Fe2 plus is larger than Fe3 plus

Practice ionic size S2 minus vs Cl minus

S2 minus is larger due to fewer protons for the same shell

Practice colored or colorless Ti4 plus

Colorless because d0

Practice colored or colorless Sc3 plus

Colorless because d0

Practice colored or colorless V3 plus

Colored because d2

Practice colored or colorless Cu plus

Often colorless because d10

Practice colored or colorless Cu2 plus

Colored because d9

Practice colored or colorless Zn2 plus

Colorless because d10

Practice remove electrons from Fe to make Fe2 plus

Remove the two 4s electrons first

Practice remove electrons from Co to make Co3 plus

Remove two 4s then one 3d resulting [Ar] 3d6

Practice red vs violet energy

Photons of violet have higher energy than red

Practice frequency change if wavelength doubles

Frequency halves

Practice what happens when electrons relax to lower energy

They emit light with energy equal to the gap

Practice what happens when electrons absorb light

They move to a higher energy level if energy matches a gap

Define valence electrons for main group

Electrons in the highest occupied energy level n

Find valence electrons from configuration example phosphorus

Phosphorus has five valence electrons from 3s2 3p3

Principal quantum number definition

Symbol n labels energy level and general size

Sublevels count in level n

Number of sublevels equals n

Orbitals per energy level formula

Total orbitals equals n squared

Max electrons per energy level formula

Max electrons equals 2 n squared

Orbitals per sublevel counts

s has 1 p has 3 d has 5 f has 7

Max electrons per sublevel

s holds 2 p holds 6 d holds 10 f holds 14

n equals 1 contents

Sublevels s; Total orbitals 1; Max electrons 2

n equals 2 contents

Sublevels s and p; Total orbitals 4; Max electrons 8

n equals 3 contents

Sublevels s p d; Total orbitals 9; Max electrons 18