Notes: 4 (2D) Land surface of Earth. Rocks and Minerals.

Land surface of earth: = 150 million square kilometers

A large part of this area is covered by overburden

Bedrock: The solid rock below the overburden.

Outcrops: The solid bedrock seen at the surface.

Rocks: Are composed of one or more minerals.

Mineral: Elements or compounds that occur naturally in the earth’s crust.

Element:Cannot be broken down into simpler substances by ordinary chemical means.

Abundant Earth Elements:
Oxygen 46.6%
 Silica 27.7% Aluminum 8.1% Iron 5%

Atom: The smallest part of an element.

John Dalton:
An English chemist who 150 years ago stated his belief that atoms make up elements.

The number of protons in the atom is called:  atomic number

The number of protons and neutrons combined in the atom is called: atomic weight

QUESTIONS

1. Atomic weight = 23

Atomic number = 11

Protons=?

Electrons=?

Neutrons=?

Element is?

QUESTIONS

2. Atomic weight = 75

Atomic number = 33

Protons=?

Electrons=?

Neutrons=?

Element is?

Atomic weight = 75
Atomic number = 33
Protons=33
Electrons=33
Neutrons=42
Element is As (Arsenic)

Atoms of the same chemical element with different atomic weights are: isotopes

Example:
Carbon12 and Carbon 14

Carbon 12 has 6 neutrons

Carbon 14 has 8 neutrons

Notice the number of protons do not change. If they did it would be a different element!!

The mass of the atom is practically the same as the sum of the  protons and neutrons

The mass of an electron is only 1/1836  the mass of a neutron or proton.

An atom that loses or gains one or more electrons and becomes charged positively or negatively is called an: ion

Ions are formed:

When some compounds dissolve in water.

By Friction between molecules: Static electricity.

By High temperatures

Positive ions unite in simple whole number ratios with negative ions.
Example: Na (Sodium)⁺
and Cl (Chlorine)^-
forms NaCl (Salt)

Metals are elements that:  lose electrons
Example: Gold, Silver, Copper, Sodium.

Non-metals are elements that:  gain electrons
Examples: Nitrogen, Oxygen, Sulfur.

Inert elements are elements that: neither gain nor lose electrons
Examples: Helium, Neon, Argon.