Neutrally charged particles in the nucleus.

(Associated with Isotopes)

Positively charged particles in the nucleus.

(Equal to Atomic Number)

An unstable isotope.

Spontaneously decaying nucleus gives off detectable particles and energy.

Capacity to cause change (ie. do work)

*Further away an electron is from the nucleus, the greater potential energy it has*

Electrons in the outermost shell

*An atom with a full valence shel is unreactive*

The 3D space where an electron is found 90% of the time

** The 1st electron shell has 1 special orbital (1s), 2nd shell has 4 orbitals (2s), and the 3rd has (2p) orbitals**

Attraction between 2 atoms resulting from the sharing of valence shell electrons or the presence of opposite charges on the atoms.

**Bonded atoms gain complete valence shells**

Sharing of a pair of valence electrons by 2 atoms.

* Valence shell must be completed*

A covalent bond between atoms that differ in electrogenativity.

*Shared electrons are pulled closer to the more electrogenative atom, making it slightly negative and the other atom slightly positive*

Attraction of a given atom to the electron of a covalent bond.

*More valence electrons > electrogenativity*

**Less valence electrons < electrogenativity**

A chemical bond resulting from the attraction between oppositely charged ions:

Cations and Anions

**Weak in Water**

A weak chemical bond that's formed when the slightly positive Hydrogen atom of a polar covalent bond in 1 moleule is attracted to the slightly negative atom of a polar covalent bond in another molecule or another region of the same molecule.

**Found between 2 polar covalent bonds**

Weak attractions between molecules or parts of molecules that result from transient local partial charges 

*Even a molecule with nonpolar covalent bonds may have positive and negative charged regions*

**Molecular shape is crucial for biological molecules to recognize and respond to one another**