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Describe an electron dot diagram.

An electron dot diagram is a model of an atom in which

By losing one valence electron, a sodium atom achieves the same electron arrangement as an atom of _____

Neon.

An ionic bond forms when _____ are transferred from one atom to another.

Is the following sentence true or false? The lower the ionization energy, the easier it is to remove an electron from an atom.

Identify two factors that determine the arrangement of ions in an ionic crystal.

Is the following sentence true or false? In a covalent bond, the atoms are held together by the attractions between the shared electrons and the protons in each nucleus.

In general, elements at the _____ of a group have a greater attraction for electrons than elements at the ____ of a group have.

In a hydrogen chloride molecule, the ____ shared electrons spend more time near the ____ atom than near the atom.

Describe a polar covalent bond.

A polar covalent bond is a covalent bond in which electrons are not shared equally.

When atoms form a polar covalent bond, the atom with the greater attraction for electrons has a partial ____ charge.

 Is the following sentence true or false? The new substances formed as a result of a chemical reaction are called products.

 Is the following sentence true or false? A chemical equation must be balanced in order to show that mass is conserved during a reaction.

Is the following sentence true or false? Because the equation N2H4 ! O2hN2 ! H2O has two nitrogen atoms on each side, the equation is balanced.

What is an oxidation-reduction reaction?

An oxidation-reduction reaction is a reaction in which electrons are transferred from one reactant to another.

 Calcium reacts with oxygen to form calcium oxide. Which reactant is oxidized in this reaction?

Is the following sentence true or false? When calcium reacts with oxygen, each calcium atom gains two electrons and becomes a calcium ion with a charge of 2–.

 False.

Is the following sentence true or false? Oxygen must be present in order for an oxidation-reduction reaction to take place.

The process in which an element gains electrons during a chemical reaction is called _____.

What is chemical energy?

Chemical energy is the energy stored in the chemical bonds of a substance.

Chemical reactions involve the breaking of chemical bonds in the reactants and the formation of chemical bonds in the _____.