Chemistry - Atoms, Elements, Compounds and Chemical Equations

Atoms

________ are neutral- they have no charge overall (unlike ions)

positive charge

It has a(n) ________ because of the protons.

Chemical changes

________ can be shown in a kind of shorthand using symbol equations.

Electrons

________ have virtually no mass.

bonds

Making ________ involves atoms giving away, taking or sharing electrons.

Isotopes

________ are different forms of the same element, which have the same number of protons but a different number of neutrons.

Symbol equations

________ just show the symbols or formulas of the reactants and products.

Compounds

________ are substances formed form two or more elements.

Atoms

________ have a radius of about 10 nanometres (1x10- (9))

Atoms

________ can have different numbers of protons, neutrons and electrons.

Proton

1 and +1

Neutron

1 and 0

Electron

Very small and -1

For example, an ion with a 2

charge, has two more electrons than protons

Methane + Oxygen

Carbon Dioxide + Water

Magnesium + Oxygen

Magnesium Oxide

2Mg + 02

2Mg0

H2S04 + Na0H

Na2S04 + H20

Electron description

move around the nucleus in electron shells and are negatively charges and tiny

Nucleus description

middle of the atom and contains protons and neutrons and is positively charged

Atomic number

tells you how many protons there are

Mass number

tells you the total number of protons and neutrons in the atom

Number of neutrons

Mass number - Atomic number

Elements description

consist of atms with the same atomic number

Atoms represented

atoms of each element shown by one or two letter symbols

Relative atomic mas calculation

sum of isotope abundance x mass number / 100

Balanced equation description

same amount of all elements

what happens when atoms react

atoms combine with other atoms to form compounds