Biology Chemistry: Atomic Structure, Bonding, and Ions Review

Atomic mass

The sum number of protons and neutrons in the nucleus.

Atomic number

The number of protons in the nucleus.

Number of neutrons calculation

Subtract the number of protons from the atomic mass.

Number of electrons

The same as the number of protons found in the element's atom.

Octet rule

When an element seeks 8 electrons in its outer shell.

Duet rule

When an element only has one shell and it's satisfied with 2 electrons.

Bonding

The process where atoms share, gain, or lose electrons to become stable and satisfy the octet rule.

Electronegativity trend

Electronegativity on the periodic table normally increases from left to right.

Highest electronegativity

Fluorine.

Lowest electronegativity

Francium.

Non-metals on periodic table

The light blue elements and the noble gases.

Valence electrons determination

The group an element is in determines how many electrons are in the outer shell.

Ionic bonds formation

Form from electron transfer between a metal and nonmetal, creating oppositely charged ions.

Example of ionic bond

NaCl.

Covalent bonds formation

Form from electron sharing between nonmetals, creating stable molecules.

Example of covalent bond

H₂O.

Electronegativity and bond type

If electronegativity is <1.7, the bond is covalent; if >1.7, the bond is ionic.

Covalent bond example

O₂.

Ionic bond example

CaCl₂.

Isotopes definition

Elements with the same atomic number but different atomic mass.

Ions

Charged atoms (either positive or negative).

Ionization reaction example

Na ---> Na+ plus an electron.

Gain an electron

Results in a negative charge.

Lose an electron

Results in a positive charge.

Neutral atom ionization

Means you have enough atoms to satisfy the octet rule and/or duet rule.