Basic atomic structure

Where are each of the 3 subatomic particles found in an atom?

• Proton: found in the nucleus

• Neutron: found in the nucleus

• Electron: found in the surrounding electron cloud (held in orbitals and shells)

Relationship between shell energy and distance from the nucleus

The energy of electron shells increases with distance from the nucleus

Valence electrons (location and function)

Electrons found in the outermost shell of an atom, involved with bonding between atoms—transfer between atoms to create stability (full valence shells)

Isotope

Atoms of the same element that have a different number of neutrons (protons and electrons are the same)

Ex: carbon-12 and carbon-14

Atomic mass

Sum of the atom’s protons and neutrons (tiny mass of electrons doesn’t impact overall mass); measured in atomic mass units/amu; bottom number of periodic table unit

Atomic number

Number of protons in an atom; ordering number on the periodic table

Atomic/electric charge

Protons minus electrons; the remaining subatomic particles dictate the charge of the atom (10 protons - 12 electrons = -2 charge)

Ion

Atom/molecule with a positive or negative charge

Cation

Positively charged ionA

Anion

Negatively charged ion

Orbital

Specific region around the nucleus where an electron can be found; can hold up to two electrons; make up subshells which then make up shells

Covalent bond

Bonds where atoms share pairs of electrons; typically between non-metals and stableI

Ionic bond

• Bond involving the complete transfer of electrons from one atom to another, creating charged ions that attract each other

• One atom wants to fill its valence shell and receives an electron from another atom

• Typically a metal transferring to a non-metal

Periods (periodic table organization)

• Rows, from 1 to 7

• Indicate the shell number of the valence/outmost shell; as well as the number of subshells within each shell

• Ex: elements in period 2: shell number 2 is the valence shell, and that shell contains 2 subshells (s and p)

Groups (periodic table organization)

• Columns, from 1 to 18

• Each element in a group shares the same number of valence/outermost electrons

• All have similar chemical behavior and reactivity