Introduction to Chemistry Quest December 2025

Atomic Mass

The mass of an atom - The mass of all the protons and neutrons in an atom (each has a mass of one unit)

Atomic Number

The number of protons in the nucleus of an atom

How do you calculate the number of neutrons in a neutral atom?

Subtract the number of protons from the atomic mass

How do you figure out the number of electrons?

Look at the atomic number (protons and electrons are the same value in a neutral atom)

What is the octet rule?

Elements seek to obtain 8 electrons in the valence shell in order to be stable

What is the duet rule?

Elements seek to obtain 2 electrons in the valence shell in order to be stable (only applicable to the first 5 elements)

What two elements does the duet rule mainly apply to?

Hydrogen and Helium (the first two elements) - their valence shell is only capable of holding two electrons

Covalent bonding

The sharing of electrons between atoms

Ionic bonding

The transfer of electrons between atoms

Lewis electron dot diagram

Only draw the electrons in the valence shell

Bohr diagram

Draw all of the shells/electrons of the atom

Where are the metals located on the periodic table?

The left (and the center)

Where are non-metals located on the periodic table?

The top right (zig-zagging staircase to seperate non-metals from metals)

Where is there high electronegativity on the periodic table?

The top right

Element with most electronegativity?

Florine

Where is there low electronegativity on the periodic table?

Bottom left corner