Chemistry Unit 3 Review: Electron Configuration and Periodic Trends

it introduced the concept of energy levels

Why is Bohr’s model significant?

Quantum

a specific amount of energy that separates energy levels

gain or lose a quantum of energy

Electrons must…to move between levels

Ground State

An electron in the lowest possible energy level

Excited State

when an electron absorbs energy and is at a higher energy level

the energy is released as electromagnetic radiation and is visible as light

If an electron falls from an excited state to a less excited state, what happens to the lost energy?

Because each element has a unique electron configuration, it emits a distinct color of light

Why are flame test colors different from element to element?

Quantum Mechanical Model

What most widely accepted atomic model that is still used today?

He develops a mathematical equation that describes the energy and location of an electron.

Why is Erwin Schrodinger’s discoveries still relevant today?

Electron Cloud/Orbital

an area where there is a 90% probability of finding an electron

s,p,d,f

Name the 4 sublevels

spherical shape

What is the shape of the s sublevel?

1 orbital

How many orbitals do the s sublevels have?

2 electrons

How many electrons can the s sublevels hold?

dumbbell shape

What is the shape of the p sublevel?

3 orbitals

How many orbitals do the p sublevels have?

6 electrons

How many electrons can the p sublevels hold?

double dumbells (4) & a hula hoop dancer (1)

What is the shape of the d sublevel?

5 orbitals

How many orbitals do the d sublevels have?

10 electrons

How many electrons can the d sublevels hold?

7

How many orbitals do the f sublevels have?

14 electrons

How many electrons can the f sublevels hold?

Aufbau Principle

A rule where electrons fill orbitals starting from the lowest energy level and work their way up to higher energy levels.

Pauli Exclusion Principle

A rule where each individual orbital can hold a maximum of two electrons and those must have opposite spins

Hund’s Rule

A rule where electrons half-fill each of the orbital in a subshell before pairing

n²

Formula for total orbitals in a shell

2n²

Formula for Maximum electrons in shell

Principle Quantum Number (n)

This quantum number shows the energy level of the last electron.

Azimuthal Quantum Number (l)

This quantum number shows the sublevel of the last electron

s=0,p=1,d=2,f=3

What are the Azimuthal Quantum Numbers that correspond to the sublevels?

Magnetic Quantum Number (m_l)

This quantum number represents a specific orientation of the orbital

Spin Quantum Number (m_s)

This quantum number represents the spin of the last electrons

one s-orbital electron promotes to the d-orbital (d⁴→d⁵)

Chromium Group Aufbau principle exception

one s-orbital electron promotes to the d-orbital (d⁹→d¹⁰)

Copper Group Aufbau principle exception

Periodic Law 

States that when elements are arranged by increasing atomic number their physical and chemical properties repeat periodically

elements share similar chemical and physical properties

Periodic Law applied to Groups

Properties change in predictable patterns

Periodic Law applied to Periods

Period

A horizontal row on the periodic table

Group

A vertical column on the periodic table

Metals

elements to the left of the staircase

High luster, high electrical conductivity, ductile, malleable

Properties of Metals

Nonmetals

Elements to the right of the staircase

non lustrous, poor electrical conductors, brittle

Properties of Nonmetals

Metalloids

Elements that touch the staircase (except aluminum)

Mix of both metallic and non metallic properties

Properties of Metalloids

Electronegativity

the tendency for an atom to attract shared electron towards itself

it increases from left to right

What is the periodic trend for electronegativity?

it decreases from top to bottom

What is the group trend for electronegativity?

Shielding effect

the ability of inner electrons to shield the outermost electrons from the nucleus

it increases from left to right

What is the periodic trend for shielding effect?

it increases from top to bottom

What is the group trend for shielding effect?

Nuclear Charge

the number of protons in the nucleus

it increases from left to right

What is the periodic trend for nuclear charge?

it increases from top to bottom

What is the group trend for nuclear charge?

Ionization energy

amount of energy required to remove a single electron from an atom

it increases from left to right

What is the periodic trend for ionization energy?

it decreases from top to bottom

What is the group trend for ionization energy?

Electron Affinity

The amount of energy released when a neutral atom gains an extra electron to become a negative ion (anion)

it increases from left to right

What is the periodic trend for electron affinity?

it decreases from top to bottom

What is the group trend for electron affinity?

Atomic Radii

The size of the atom

it decreases from left to right

What is the periodic trend for atomic radii?

it increases from top to bottom

What is the group trend for atomic radii?

Ionic Size

the size of an ion

it decreases from left to right

What is the periodic trend for ionic size?

it increases from top to bottom

What is the periodic trend for ionic size?

Cation

A positive ion that forms when it loses electrons

smaller because they lose electrons

Is a Cation bigger or smaller than a neutral atom?

Anion

A negative ion that forms when it gains electrons

larger because they gain electrons

Is a Antion bigger or smaller than a neutral atom?