EAS- introduction to minerals

what is a mineral

1. a solid at surface temp and pressure

2. a regular internal structure of atoms (crystalline)

3. narrowly defined chemical composition

what is a gemstone

precious/ semi precious minerals or rocks used as decoration

nucleus

tiny part of atom but has almost all mass

atomic number

number of protons in nucleus

elements

defined by number of protons in nucleus

atomic mass

total number of protons and neutrons in the nucleus

electrons

• arranged in shells/ orbitals

• # is same as atomic #

isotopes

• same chemical property, different mass via different # of neutrons in nucleus

what controls how an atom will react chemically

arrangement of outermost electron shell

ionic bonds

• electron transferred to make noble gas configuration

• forms cations/ anions

• ions attract and form lattice arrangement

with ionic bonding, shape of crystal reflects….

arrangement of atoms

covalent bonds

• atoms share electrons

• occur between atoms of same OR different type of atoms

• ex. carbon forms diamond OR graphite

• strongest type of bond

structural difference between diamond/ carbon

• diamond is covalently bonded in every direction= same strength in every direction

• graphite is covalently bonded in layers, but each layer is bonded via VDW bonds = weaker

metallic bonds

• atoms lose electrons to form a gas of shared electrons

• extreme form of covalent bonding

Van Der Waals bonding

• an extremely weak bond without available electrons to form an attraction

• ex. between sheets in graphite