Study Guide for Chapter 11 and 12 Test

Chemical bond

A force that holds two or more atoms together.

Valence electron

The outermost electron of an atom that participates in chemical bonding.

Covalent bond

A chemical bond formed when two atoms share one or more pairs of valence electrons.

Molecule

Two or more atoms that are held together by covalent bonds that act as a unit.

Polar molecule

A molecule with an unequal sharing of electrons.

Nonpolar molecule

A molecule that shares electrons equally.

Chemical formula

A group of chemical symbols and numbers that represent the elements and the number of atoms of each element that make up a compound.

Electron dot diagram

A model that represents valence electrons in an atom as dots around the element’s chemical symbol.

Ion

An atom that is no longer neutral because it has lost or gained valence electrons.

Ionic bond

The attraction between positively and negatively charged ions in an ionic compound.

Metallic bond

A bond formed when many metal atoms share their pooled valence.

Chemical equation

A description of a reaction using element symbols and chemical formulas.

Subscript

Describes the number of atoms of an element in a compound.

Reactant

A starting substance in a chemical equation.

Product

A substance produced by a chemical reaction.

Law of Conservation of Mass

A law that states that the total mass of the reactants before a chemical reaction is the same as the total mass of the products after the chemical reaction.

Coefficient

A number placed in the front of an element symbol or chemical formula in an equation.

How does the distance from the nucleus affect the attraction of electrons?

Electrons in energy levels closest to the nucleus are strongly attracted to it, while electrons in energy levels farthest from the nucleus have a weak attraction to the nucleus.

How does the energy level of an electron relate to its energy amount?

Electrons closest to the nucleus have the least amount of energy because they are at the lowest energy level. Electrons farthest away from the nucleus have the greatest amount of energy because they are at the highest energy level.

How many electrons in its outer ring make an element stable?

An element that has 8 electrons in its outer ring becomes stable.

Which energy level is involved in chemical bonding?

The outermost energy level is involved in chemical bonding.

What is the trend for atomic number as you move from left to right on the periodic table?

The atomic number increases by 1 as you move from left to right on the periodic table.

Why are Noble gases chemically stable and non-bonding?

The Noble gases are chemically stable because they have 8 valence electrons in their outer level and do not form bonds.

Why is a water molecule polar?

A water molecule is polar because the shared electrons are pulled closer to the oxygen atom than the hydrogen atom. The oxygen atom has a partial negative charge, and the hydrogen atom has a partial positive charge.

Why is a carbon dioxide molecule nonpolar?

A carbon dioxide molecule is nonpolar because the shared electrons are pulled equally by the carbon atom and the oxygen atoms.