MCAT Chem 1

An atom is composed of a Nucleus surrounded by at least one Electron

A nucleus is composed of Neutrons (Neutral and heavier) and Protons (positively charged and slightly lighter)

Associated terms Nucleon, Strong Nuclear Force, Quark

An electron is a very small particle (negatively charged) which orbits the nucleons.

Note: The space between the nucleons, or nucleus, and the electrons create the bulk of the atom.

All atoms are elements and thus can not be broken down further by chemical means. Elements are the building blocks of all compounds.

The Letter symbol and the number of Protons are always the identifyers of elements every other label can vary.

Isotopes are atoms of the same element which have a different number of nuetrons and thus a different mass.

Note: the number of protons always remains the same.

Atomic weight is weighted average of the masses of the isotopes for an element. Mass is listed in amu or u

Formula to Calculate moles:

Is the number of amu in one gram

Periods: horizontal rows
Groups: Columns
Families of elements are as follows:
1. Metals: Alkali, Alkaline Earth, Transitional
2. Metaliods: thin diagonally flowing group
3. Non-metals: Covalent and pi bonding, Halogens, Nobel Gases

1. Take on positive charge in bonds
2. Form ionic bonds with oxygen (accept BeO)
3. Ductile
4. Malleable
5.Conduct heat and electricity
6. Lustrous

Alkali Alkaline
Lower melting point Higher melting point
Highly reactive Less reactive
Softer and less dense Harder and more dense
+1 cation +2 cation

Non descript some characteristics of metals and some characteristics of non metals

1. Pi bond forming C, N, P, S, O
2. Halogens typically take on -1 charge however all but flourine can take on positive charges when paired with a highly electronegative atom