Atoms and the Periodic Table

Kinds of Matter Elements:

Made of only one type of atom – if the substance isn’t in it’s very own box on the periodic table, it isn’t an element.

Examples: Carbon Copper

Elements Some elements

have a single letter as their symbol.

Other elements have 2 or more letters for their symbol. Notice that only the first letter is capitalized.

Kinds of Matter Compounds

Two or more elements chemically combined to form a new substance.

Sodium (Na) is a metal that explodes in water.

Chlorine (Cl) is a poisonous green gas.

Together NaCl makes a new substance: table salt.

Kinds of Matter

Mixture: Elements and/or compounds mixed

together without being chemically combined.

e.g. Chocolate chip cookies – the chips are not chemically combined with the cookie.

Structure of an Atom Nucleus

Protons: + charge Neutrons: no charge

(neutral) Electron Cloud

Electrons: - charge Orbit the nucleus Very little mass

Structure of an Atom Atomic Number

Number of protons All atoms of an

element contain the same number of protons. e.g. all silver atoms have 47 protons.

Atoms have the same number of electrons as they have protons (atoms are neutral)

47

Ag 107.8682

Role of Electrons Form bonds between atoms

In carbon dioxide (CO2) the oxygen atoms (O) stick to the carbon atom (C) because all 3 atoms share electrons to make a bond.

Physical Change A change from one phase of matter

into another. (e.g. solid melting into a liquid)

A change into a different shape or texture, but not a change into a new substance. (e.g. cutting or bending a substance)

Dissolving Amount of matter (# of grams) does NOT

change.

Chemical Changes

A reaction that produces a new substance.

The mass of the reactants (the things you add together) is the same as the mass of the products (the substances produced by the reaction) Nope, this one just releases CO2 gas

Now, this would be fun.