Chem: electrons

isotopes

atoms of the same element with different numbers of neutrons, resulting in different mass numbers.

mole

the amount of a substance that contains as many particles as there are atoms in 12g carbon-12

Quantum numbers

specify the properties of atomic orbitals & the properties of electron orbitals

Principle Quantum number 

indicates the main energy level occupied by the electron (n²)

Angular momentum quantum number

indicates shape of the orbital (l)

how many electrons in s block

2

how many electrons in p block

6

how many electrons in d block

10

how many electrons in f block

14

characteristics of s block

metals, reactive, found in compounds

characteristics of p block

diverse reactivity, metals

characteristics of d block

shiny, nonreactive, good conductors, high melting point

characteristics of f block

radioactive, metals

magnetic quantum number

indicates the orientation of the orbital around the nucleus (m)

spin quantum number 

½ or -½ 

Aufbau principle

an electron occupies the lowest-energy orbital that can recieve it

Pauli exclusion principle 

an orbital that can hold 2 electrons of opposite spin, direction of the arrow determines the electron spin 

Hund’s Rule 

orbitals of equal energy are each occupied by 1 electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin

Electron configuration

ending is period # and group #

noble gas configuration

bracket the element one row above

Atomic Radii trends

Increase as you move down in groups, decrease across periods

Ion

an atom or group that has a positive or negative charge

Ionization

the process that results in the formation of an ion

Ionization energy

energy required to remove one electron from a neutral atom of an element

Valence electrons 

electrons available to be lost, gained, or shared in the formation of chemical compounds 

Electronegativity 

measure of the ability of an atom or compound to attract electrons (increases across periods, decrease down the groups)