(32) Unit 7 Part 1

Why do noble gases typically not form compounds?

They have a full outer energy level (octet) and are stable.

What are the three general types of chemical bonds?

Ionic bonds, covalent bonds, and metallic bonds.

What is an ionic bond?

Ionic bonds involve the complete transfer of electrons from one atom to another.

What causes ions in ionic compounds to stick together?

Electrostatic attraction between opposite charges.

Explain the properties of ionic compounds.

Ionic compounds have high melting points, are brittle solids at room temperature, are soluble in water, and conduct electricity when molten or dissolved.

What defines a covalent bond?

Covalent bonds are formed when nonmetals share electrons.

What is the general behavior of covalent compounds in terms of melting points and electrical conductivity?

Covalent compounds generally have low melting points and are poor conductors of electricity.

What is electronegativity?

Electronegativity is the tendency for an atom to attract a shared pair of electrons when bonded to another atom.

How does electronegativity vary across the periodic table?

Electronegativity increases across a period (left to right) and decreases down a group (top to bottom).

What denotes an ionic bond in terms of electronegativity difference?

A difference of 2 or higher indicates an ionic bond.

What are Lewis dot structures used for?

Lewis dot structures are models that show the valence electrons in an atom and how they bond.

How do you determine the number of valence electrons for an atom?

Based on the group number in the periodic table: Group 1 has 1, Group 2 has 2, and so on.

What is a lone pair of electrons in Lewis dot structures?

Lone pairs are pairs of valence electrons that are not involved in bonding.

What is a single bond and how is it represented?

A single bond is formed by sharing one pair of electrons and can be represented by a single line or stick.

What are the three types of bonds in Lewis structures?

Single bond (one pair of shared electrons), double bond (two pairs of shared electrons), and triple bond (three pairs of shared electrons).

How do you denote the charge of a polyatomic ion in a Lewis structure?

Put brackets around the structure and indicate the charge outside the brackets.

What is a resonance structure?

Resonance structures are two or more valid Lewis structures for a single molecule that cannot be represented accurately by just one structure.