Atomic Structure and Electron Shells (Video Notes)

Vocabulary flashcards covering atomic mass, subatomic particles, electron shells, valence electrons, bonding, and electronegativity as described in the notes.

Dalton (Da)

A unit of atomic mass; 1 Da is about 1/12 the mass of a carbon-12 atom (approximately 1.66×10^-27 kg).

Proton

Positively charged subatomic particle in the nucleus; mass ~1 Da and determines the atomic number.

Electron

Negatively charged subatomic particle orbiting the nucleus; much lighter than a proton.

Electron shell

Concentric regions around the nucleus where electrons reside; shells have maximum capacities.

First shell capacity

Holds up to 2 electrons.

Second shell capacity

Holds up to 8 electrons.

Third shell capacity

Holds up to 18 electrons.

Fourth shell capacity

Holds up to 32 electrons.

Valence electrons

Electrons in the outermost shell that determine bonding and reactivity.

Full valence shell

An outer shell filled to its maximum capacity, giving chemical stability.

Octet rule

Many elements are most stable when their outermost shell has eight electrons.

Gain electrons

Process by which an atom adds electrons to fill its outer shell, forming a negative ion.

Lose electrons

Process by which an atom removes electrons to empty its outer shell, forming a positive ion.

Share electrons (covalent bonding)

Electrons are shared between atoms to satisfy outer-shell stability.

Electronegativity

Tendency of an atom to attract electrons in a bond; fluorine is the most electronegative element.

Fluorine

Element with the highest electronegativity; very strong at attracting bonding electrons.