DAT Bootcamp: General Chemistry

How to fill electron orbitals?

based on the s, p, d, and f blocks

Hund's Rule

states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

Aufbau Principle

An electron occupies the lowest-energy orbital that can receive it

The electrons whose orbitals are __________________ away from the nucleus (those with the largest principle quantum number, n) are the atom's valence electrons.

furthest

The ______________ electrons are the highest energy elections and the ones that play a role in chemical reactions.

valence

For elements in the _____ block, the ___ shell electrons are also valence electrons.

d

The higher an electron's principle quantum number (n)...

- the further the distance from the nucleus

- the higher the energy

- the higher the reactivity

What are the five exceptions in electron configuration?

Chromium [Ar] 4s¹ 3d⁵

Molybdenum [Kr] 5s¹ 4d⁵

Cu [Ar] 4s¹ 3d10

Ag [Kr] 5s¹ 4d10

Au [Xe] 6s¹ 4f14 5d10

Cr & Mo move an electron down in order to...

get their electrons unpaired

Cu, Ag, Au move an electron down in order to...

to have it in a lower energy state and be more stable

Paramagnetic

have an unpaired electron

Paramagnetic substances are ______________ to magnets.

attracted

Diamagnetic

all electrons are paired

Diamagnetic substances are slightly ___________ by magnets.

repelled

If an element has an _______ number of electrons then it is paramagnetic.

ODD

If an element has an _________ number of electrons, then it is paramagnetic OR diamagnetic. You have to use the energy diagram to figure it out.

EVEN

Energy of a Photon

hf = hc÷λ

The energy of a photon is directly related to its ______________.

frequency

The energy of a photon is inversely proportional to its ____________.

wavelength

As the energy of a photon increases, the frequency will ________________ and the wavelength will ________________.

increase; decrease

Frequency =

1/λ

N₂ is

diamagnetic

O₂ is

paramagnetic

Octet Rule

refers to the tendency of atoms to prefer to have eight electrons in the valence shell, so that they can behave like noble gases

When atoms gain an electron they become ___________ charged.

negatively

When atoms lose an electron, they become ___________ charged.

positively

Compounds

are molecules comprised of two or more different elements bonded together

Metals v. Nonmetals

helps to determine if an ionic or a molecular compound is formed

Ionic Compounds

metal + non-metal --> through ionic bonds

(exceptions being the polyatomic ions)

Molecular Compounds

non-metal + non-metal --> through covalent bonding

_____________ determines if the sharing between electrons is equal or unequal.

Electronegativity

___________ Covalent Bonds are molecular compounds with an uneven sharing of electrons caused by a significant different in electronegativity.

Polar

They have partial positive or negative charges

______________ Covalent Bonds occur when nonmetal atoms do not have a significant electronegativity difference between them.

Nonpolar

They do not have partial charges.

Lattice Energy

the energy required to completely separate an ionic compound's cations from its anions

The larger the charges =

the larger the lattice energy

The shorter the bond distance =

the larger the lattice energy

Hydrogen only wants ______ electrons.

2

Beryllium only wants ______ electrons.

4

Boron and Aluminum only want ______ electrons.

6

_________ row and lower can have more than 8 electrons if needed.

Third

Each triple bond is one _____ and two _____ bonds.

σ; π

Each single bond is one _____ bond.

σ

Each double bond is one _____ and one ________ bond.

σ; π

Formal Charge =

(valence electrons) - (one for each dot) - (one for each bond)

A __________ is a column and elements within here have similar properties.

group

A ______________ is a row and elements within here do not necessarily have similar properties.

period

Group 1 = ________ Metals

Alkali

low ionization energies because they want to lose an electron to feel like a noble gas; it is a lot easier for them to shift to the right than the left

- explosive with water

- form ionic compounds

What is the common formula of alkali metals?

M(s) + H₂O(l) --> MOH (aq) + 1/2H₂(g)

- extremely exothermic

Group 2 = ___________ ____________ Metals

Alkaline Earth Metals

- low ionization energies (but not as low as gorup 1)

- Do react with H₂O, but not as violently as group 1

- Generally get more reactive as you go down the group.

Group 7A/17 = ______________

Halogens

- High electronegativities/electron affinities

- They are easily reduced and want to have an extra electron

- Highly reactive with metals

- They are only one valence electron away from full octet

Group 8A/18 = ______________

Noble Gases

- they are inert

D block = _____________ Metals

Transition

- often form brightly colored compounds due to the way that d-orbitals allow electrons to absorb colored light and be promoted to higher energy levels

- multiple oxidation states (ie: iron)

Group 6A = ____________ Group or the Chalcogens

- two forms of molecular oxygen O₂ and O₃.

- O₂ is a good oxidizing agent (oxidant), but O₃ is an even better oxidizing agent

- Metals like to react with oxgen to form metal oxides

Atomic Radius

the distance from its nucleus to the outside of its outermost orbitals

Bond Length =

atomic radius of first element + atomic radius of second element

An increase in the number of energy shells (n) -->

an increase in size

As the effective nuclear charge increases --->

the size of the element decreases

When dealing with atoms of the exact same element, if you give an atom an electron (create an anion) the atom _________ in size.

increases

When dealing with atoms of the exact same element, if you take away an electron from an atom (create an cation) the atom _________ in size.

decreases

Isoelectronic Series

if you have a group of atoms or ions that are from different elements but have the same total number of electrons

Ionization Energy

the amount of energy required to strip an electron from an atom

Why is ionization energy opposite of atomic radius?

The smaller the atom, the closer the electrons are to the nucleus meaning they are being pulled very closely. The larger an atom, the further away electrons are from the nucleus, making it easier to pull them away.

Electron Affinity

the energy produced when an atom accepts an electron; the opposite of ionization energy

Unlike electronegativity, _____________ not fluorine has the highest electron affinity.

chlorine

The __________ gases are excluded from the electron affinity trends.

noble

Be electron affinity is around _______.

0; it has a completely filled 2s subshell

N electron affinity is around _______.

0; it has a half filled 2p subshell

What is the formula for Kelvin?

K = °C + 273

Volume is measured in __________.

liters

1 cm³ =

1 mL = 1cc

What is the formula for Pressure?

P = Force/Area

1 atm =

760 torr = 760 mmHg

Ideal Gas

a theoretical gas whose behavior can be predicted by the ideal gas law.

Ideal Gas Assumptions

1. volume or size is insignificant

2. collisions are elastic

3. average kinetic energy depends only on pressure

Gases behave most ideally at ________ temperatures and ___________ pressures.

high; low

Boyle's Law:

volume is inversely related to pressure

Charle's Law:

volume is directly related to temperature

Avogadro's Law:

volume is directly related to the number of gas molecules

Combined Gas Law:

P₁V₁/nRT₁=P₂V₂/nRT₂

Ideal Gas Law:

enables use to calculate one that we don't know when dealing with PV=nRT

Gas Density =

P(MM)/RT

Dalton's Law of Partial Pressure =

Ptotal = Pa + Pb ...

How to determine one of the partial pressures?

Pa = Xa × Ptotal

Types of Intermolecular Forces:

1. Hydrogen Bonding (strongest)

2. Dipole - Dipole

3. London Dispersion Forces (hydrocarbons, other nonpolar molecules)

H bonding in H₂O:

partial charges cause them to stack on eachother

H bonding in NH₃:

partial charges cause them to stick on each other

H bonding in HF:

partial charges cause them to stick together

Hydrogen Bonding is strong because of the ______ electronegativity of F, O, N.

high

Dipole Dipole Forces

cause when two bonded atoms have significant electronegativity difference - causes molecule to have partial neg on one atom and a partial positive on another

Dipole Dipole only apply to...

polar, non-ionic molecules that do not have an H bonded to an O, N, F

Dispersion Forces

nonpolar; there is not an uneven sharing of electrons because they have similar electronegativities; they have momentary partial charges from the electrons moving around each other

If you have two molecules with only dispersion forces, the __________ molecule will have a higher B.P.

larger

- it has more dispersion forces

Higher IM forces = ________ B.P.

higher

Higher IM forces = ________ Heat of Vaporization

higher

needs more heat to get molecules to separate and turn into a gas

Higher IM forces = ________ Viscosity

higher

Higher IM forces = ________ Surface Tension

higher

the greater amount of weight the surface can contain

Higher IM forces = ________ Vapor Pressure

lower

Vapor Pressure

the upward pressure exerted by the substance on the atmosphere

Boiling occurs when the pressure exerted by the liquid towards the atmosphere ________ the pressure exerted by the atmosphere down on the liquid molecules.

equals

@ Higher altitudes, there is lower atmospheric pressure and the boiling point __________.

decreases