Chemistry

Unit 2

Atomic Radius definition

Size of atom and its electron cloud

Orbital definition

A description of where the electrons in an atom most likely are. One orbital holds two electrons.

Aufbau’s Principle

Electrons fill lowest energy levels first

Hund’s Rule

Electrons fill orbitals in order to maximize unpaired electrons

Pauli Exclusion Principle

No two electrons in the same orbital can have the same spin

Ions definition

Charged particles

Octet Rule

All atoms want to have 8 valence electrons

Ionization Energy definition

Energy required to remove an electron

Ionization energy increase from…

L→R, B→T

Electron Shielding definition

Blocking effect of full energy shells (s^2 p^6)

Electron Shielding increases from…

T→B, R→L

Reactivity/Metallic Character definition

Tendency of an atom to lose an electron

Reactivity/Metallic Character increases from…

R→L, T→B

Electronegativity Definition

The tendency of an atom to gain an electron

Electronegativity increases from…

L→R, B→T

The bottom left of the periodic table has…

The most shielding and least attraction

The top right of the periodic table has…

The least shielding and most attraction

Where are the alkali metals?

Group 1 (with the exception of Hydrogen)

Where are the alkaline earth metals?

Group 2

Where are the transition metals?

Group 3-12

Where are the halogens?

Group 17

Where are the noble gases?

Group 18

Where are the metals?

Everything to the left of the staircase

Where are the nonmetals?

Everything to the right of the staircase

Characteristics of metals

Low energy, lose electrons, positive ions, no electrons

Characteristics of nonmetals

High energy, gain electrons, negative ions, 8 electrons

What is block S?

Group 1 and 2

What is block P?

Group 13-18

What is block D?

Group 3-12, but only the ones attached to the table

What is block F?

Group 5-18, but the only the ones at the bottom, unattached from the main part of the table

What does an orbital diagram look like?

It’s doesn’t look like your typical diagram, it has the one sided arrows after the subshell name

What does isoelectronic mean?

If two elements are isoelectronic, they have the same number of electrons, different number of protons, and the neutrons are unclear. These are elements with brackets around them and a charged number in the right corner that help them get to the closest noble gas.

How do you easily find the number of valence electrons an element has?

Count how many numbers over it is from left to right; that’s its valence electron number

What does electron configuration look like?

The subshell names alongside the number of electrons the element holds in the top right corner (2s^2)

What are Lewis Dot Diagrams?

Simple diagrams that show the number and location of valence electrons

What are metals?

Elements with properties

What is a photon?

A wavelength of light

What are the 3 steps for abbreviated electron configuration?

1. Identify last electrons of the element
2. Identify the noble gas in period above
3. Fill from next s shell to last electrons

Why do atoms get larger as you go down a group?

Because the more you go down a group, the more electron shielding. This means that there is a greater distance between the valence electrons and nucleus, so the atomic radius increases.

Why do atoms get atoms get smaller as you move left to right?

Because as you go left to right, there are more protons. These protons and electrons attract and shrink the electron cloud. Along with this, there is less shielding, so the nucleus and valence electrons are close and condensed.