To satisfy their outer energy levels and make them full of electrons.
100
What do the vertical columns tell you about the elements?
their valences
100
When is an atom unstable?
When its outer energy levels are NOT full
200
In a chemical formula, the number of each type of atom in is compound is show by number called....
subscripts
200
What are dot diagrams used to represent?
Valence electrons or outer shells
200
What kind of chemical bond occurs when atoms share electrons?
covalent
200
What do the horizontal periods tell you about the elements?
The number of energy levels
200
Where can electrons be found?
Somewhere in the energy levels but cannot necessarily be pinpointed because the energy they have causes them to bounce around
300
What IS a chemical formula?
the elements that make up a compound and the exact number of atoms of each element
300
What types of elements are gases?
non-metals
300
What type of bond occurs when an equal exchange of electrons occurs? (transfers)
ionic bond
300
Of what is the atomic number a representation?
The number of protons and thereby its identification
300
How many electrons are found in the first two energy levels?
2 and 8 respectively
400
What is the symbol for sodium?
Na
400
What is a particle that moves around the nucleus?
an electron
400
Why is water a non-polar molecule?
It has both negative and positive ends.
400
What is the mass number?
An atom's protons and neutrons
400
What happens to the properties of an element once it becomes a compound?
their properties change; for example, the components of water are gases until they combine; then they become liquid.
500
What is the symbol for neon?
Ne
500
What are quarks?
Particles of matter that make up protons and neutrons
500
Why is water known as the universal solvent?
It is a polar molecule held together by covalent bonds.
That gives it the unique property of being able to dissolve many solutes, creating a solution out of most compounds
500
Why is group 18 stable and what are these elements called?
Their valences are full and thereby called the "Noble Gases"