Earth Science 1121H Atoms and Bonding

What are minerals composed of

atoms

Mineral

- Naturally formed
- Inorganic solid with a specific chemical composition
- a regular crystal structure (orderly arrangement of atoms)

Diffraction

The bending of a wave as it moves around an obstacle or passes through a narrow opening

All matter is composed of

elements (i.e. O for Oxygen, C for Carbon)

Compound

mixture of elements (I.e. Carbon Dioxide CO2)

All elements are composed of

atoms

Atoms

the smallest individual particle that retains the distinctive properties of a chemical element

Structure of atoms

nucleus, protons, neutrons, electrons

Nucleus

protons and neutrons

Elections

orbit nucleus and carry negative charge

Atomic Number (Z)

number of protons

If the number of protons equals the number of electrons

The nucleus carries a neutral charge

Atomic Mass Number (A)

Number of protons and neutrons

Isotopes

Atoms of the same element that have different atomic mass number but same atomic number

Most of the mass in an atom is in

nucleus

Innermost orbital shell can hold

max 2 electrons

Other orbitals (not the innermost) can hold

a max of 8 or more electrons

In multi-electron atoms

orbitals are filled in sequence from the innermost to outermost

inert elements

have their outermost energy level fully occupied by electrons
- stable electronic configuration
- helium and neon

How do atoms achieve stability?

by losing, gaining, or sharing electrons, filing their outermost shell with atoms of other elements to form compounds

How do chemical compounds form

when atoms of different elements combine in a specific ration

Chemical bond

the force that holds two atoms together

Ionic bonding

A chemical bond that is formed when one element transfers an election to another element which binds them together
- held together by charge differences

Covalent bonding

a chemical bond formed when atoms share one or more pairs of electrons

Metallic bond

a bond formed by the attraction between positively charged metal ions and the electrons around them

Van der Waals bond

weak bonds of electrostatic attraction