Chemistry

What is chemistry?

Study of the properties of matter and how they change

What is matter?

Anything that has mass and takes up space

Structure of an Atom

Elements on the Periodic Table

• Atomic Mass– Average mass of elements atom

• Atomic Number– Number of protons in the nucleus

• Symbol – Letter (s) used to represent the element

• Group– Columns of elements

• Period– Rows of elements

Drawing an Atomic Model

What is a compound?

How do you find the Molecular Weight of a compound?

Electron Dot Diagrams

3 States of Matter

4th state - PlasmaState of matter found at extreme conditions. Matter found on the sun is

in this state.

Gas-like mixture of free electrons and atoms stripped of electrons

examples: man-made That found in plasma displays and TVs

Inside fluorescent lamps (low energy lighting),neon signs Rocket exhaust

naturalLightning The ionosphere The Northern Lights fire

Types of Matter

Mixturea combination of two or more substances that are NOT

chemically combined

Pure Substancea single kind of matter that has a specific make-up

Isotopes

When an element has a different number of neutrons

Carbon Isotopes

Who was Mendeleev?Russian scientist who recognized a

pattern with the elements.

Created the Periodic Table.

• Alkali Metals– Very reactive and do not occur freely in nature

– Explode when exposed to water

– Conduct electricity

• Alkaline Earth Metals– Very reactive and do not occur freely in nature

• Transition Metals– ductile and malleable, and conduct electricity and heat – iron, cobalt, and nickel, are the only elements known to produce

a magnetic field.

• Other Metals– ductile and malleable – variable oxidation states

• Non-Metal– are very brittle – no metallic luster, and do not reflect light

• Halogen– called "salts". – Exist at room temp as the 3 states

» Solid- Iodine, Astatine » Liquid- Bromine » Gas- Fluorine, Chlorine

• Noble Gas– Most stable elements