The First 20 Elements in the Periodic (Updated)

Hydrogen

Helium

Lithium

Beryllium

Boron

Carbon

Nitrogen

Oxygen

Fluorine

Neon

Sodium

Magnesium

Aluminum

Silicon

Phosphorus

Sulfur

Chlorine

Argon

Potassium

Calcium

+1, +2, skip 10 columns, +3, +4/-4, -3, -2, -1, 0 (+ nums means that how many in valence shell, - is how many away from full valence) exception is helium but its inert

electrons are usually lost

electrons are usually gained

Electrons can be gained or lost

valence shells are filled and the element is nonreactive/inert

The metal loses electrons and the nonmetal gains electrons.

Enough to complete the shell of the nonmetal and empty the shell of the metal. If that isn’t possible more atoms may need to be added to the mix.

Electrons are lost or gained.

Electrons are shared between atoms to complete shells.

The atom has a positive charge

The atom has a negative charge

Positively charged

Negatively charged

Use the atomic number of the element from the periodic table.

The number of protons in an atom is equal to its atomic number.

To find neutrons in an atom, subtract the atomic number from the atomic mass.

Molecules

A crystal lattice

Physical:
Soft, low melting, shiny metals: conduct heat and electricity
Chemical:
React vigorously with acids, water, oxygen, and halogens. The reaction with water generates hydrogen gas and a base.
Valence Number:
1

Physical:
Harder, higher-melting metals: conduct heat and electricity
Chemical:
React with acids, water, oxygen, and halogens, but not as violently as alkali metals. Reaction with water generates hydrogen gas and a base, unlike alkali metal bases, these are not too soluble in water, just like mud or “earth”.
Valence Number:
2

Physical:
Some are gases, others liquid, and others solids at room temp. No other family is found in all three states at room temperature. Poor conductors.
Chemical:
React with most metals, and form diatomic molecules. F₂ is so reactive that it will attack gases that would not normally react.
Valence Number:
7

Physical:
 All gases are at room temperature. Poor conductors.
Chemical:
Generally, not chemically active. None of the noble gases are flammable. They will only react with strong electron muggers
Valence Number:
8

1, 2, skip 10, 3, 4, 5, 6, 7, 8

Fluorine, the closer you get to it (rows and columns) the more electronegative the element. Least electronegative goes in the center for a lewis structure except hydrogen.