Ionic & Covalent Bonds

What is a chemical bond?

Mutual electrical attraction between the nuclei & valence electrons of different atoms.

Explain the difference between ionic and covalent bonds in terms of electrons.

Covalent bonds share electrons --- In ionic bonds, electrons are attracted to the nucleus of another.

How does a polar covalent bond differ from a non-polar covalent bond?

Polar--> unequal sharing of electrons Non-Polar---> equal electron sharing

Define "molecule"

Neutral group of covalently bonded atoms.

What is a molecular formula?

Type and number of atoms needed to make a molecule.

Longer bonds tend to be ___________ than shorter bonds.

Weaker

How many valence electrons do atoms seek to achieve?

8

Define an ionic compound.

Postitive and negative ions that have a net charge of zero.

What is an anion?

A negative ion

What is a cation?

A positive ion

What is the difference between a covalently bonded "molecule" and an ionicly bonded "crystal" in terms of atoms?

Ionic-lowest ratio Covalent- exact #

How do covalent and ionic bonded substances differ in properties?

Covalent-->low melting point, don't conduct electricity, don't dissolve in water Ionic--->high melting point, conduct electricity, dissolve in water

Ammonia is polar because its shape is _____________.

Pyramidal

What are the 3 types of bond?

Covalent, Ionic, & Metallic.

What is the difference between polar and non-polar bonding?

Polar---> unequal sharing of electrons Non-Polar---> equal sharing

If the difference in electronegativity is between two atoms is less that 1.0 it is (1), if the difference in electronegativities is greater than 1.7 it is (2) , & if the difference is between 1.0 & 1.7 it is (3)_.

1. Non-Polar Covalent

2. Ionic

3. Polar Covalent

When electrons are shared between atoms, are the electrons in a higher or lower energy state than when they are in separate atoms?

Lower

What is a molecule?

Covalently bonded atoms.

A _________________ shows the number & type of atoms in a molecule.

Molecular Formula

The attraction between the (1)_ of one atom and the (2)_ of another atom cause the potential energy to be at its lowest and a bond to form.

1. Nucleus

2. Electrons

Define "bond length".

The average distance between 2 atoms.

Define "bond energy". What compounds are more stable: ones with high bond energy or ones with low bond energy.

Bond energy is energy required to break a bond. Compounds with high bond energy are more stable.

As bond length increases the bond energy ____________.

Weakens

Shorter bonds are __________ than longer bonds.

Stronger

State the octet rule.

All atoms want 8 valence electrons.

What is an unshared pair of electrons?

Unbonded pairs of electrons on the center atom.

Write the formula unit for the ionic compound formed by Ca2+ and Br-

CaBr2

What kind of structure do we find ionic compounds in?

Crystals

Explain the metallic bond.

Attraction between metal atoms and surrounding electrons.

List some properties of metals.

Free electrons, ductile, malleable.

What is an intramolecular force?

Forces of attraction between molecules.

What are the three types of intramolecular forces? List them in order from strongest to weakest.

Dipole-Dipole, Hydrogen, London Dispersion (Van Der Waals)

Which intramolecular force holds non-polar molecules together?

London Dispersion (Van Der Waals)

Word to describe a molecule with an unequal charge distribution.

Dipole

Type of bond formed between an active metal and a nonmetal.

Ionic

The simultaneous attraction of electrons for the nuclei of two or more atoms is a chemical ______________.

Bond

Bonding that is responsible for the relatively high boiling point of water.

Ionic

Type of covalent bond found in diatomic molecules,

Nonpolar

Particles formed from covalent bonding.

Molecules

Compounds with both ionic and covalent bonds contain this type of ion.

Polyatomic

Type of bond found in aluminum foil

Metallic

The formulas of ionic compounds must be expressed as ____________ formulas.

Empirical

The shape of a water molecule.

Bent

Type of bond found between nonmetals.

Covalent

Type of covalent bonding that is found in the diamond.

Network

Type of covalent bond found between atoms of different electronegativity values.

Polar

Force of attractive between nonpolar molecules.

Van Der Waals

Element with the highest electronegativity value.

Fluorine