Chapter 8 Review-CHE1210 Exam #2

What are covalent bonds?

Bonds in molecular compounds where electrons are shared.

What are ionic bonds?

Bonds in ionic compounds where electrons are transferred from one atom to another.

What is lattice structure?

3D structure showing when anions and cations bind

What is lattice energy?

The energy released when solid salt is made from a gas phase anion and cation.

T/F: Lattice energy is always exothermic/negative

True

Why is lattice energy negative?

When bonds form, the potential energy of the system decreases.

Between CaO and BaO, which one has the larger lattice energy?

CaO, because the distance between them is smaller, as Ca has a smaller atomic radius compared to Ba.

Why do metals tend to form cations?

They have small IE (ionization energy), it takes little energy to remove electrons

They have small EA (electron affinity), and normally doesn't want extra electrons

Why do non-metals tend to form anions?

They have large EA (electron affinity), easy to add electrons.

They have large IE (ionization energy), takes lot of energy to remove electrons.

What is the octet rule?

Electrons will want to gain/lose electrons until their outer/valence shell has 8 electrons.

For transition metals, which of the following "d" configurations are the most stable (there)

A. 3d(2), 34(4)

B. 3d(1), 3d(9)

C. 3d(3), 3d(8)

D. 3d(5), 3d(10)

D. 3d(5) (half-filled d subshell), 3d(10) (exactly filled d subshell)

(*Transition metals will aim to achieve one of these two states)

In lewis structures, what are the dots around the element?

It's valence electrons.

T/F: The group an element is in typically tells you how much valence electrons it has (given it's in 1A-8A, not B)

True

What is the attracting force that forms covalent bonds?

Nuclei of two electrons see valence electrons can be shared, as the valence electrons get closer together, the distance between the closes, energy releases.

What is the repelling force in covalent bonds?

Two positively charged ions see each other, and repel each other (as positive and positive tend to repel), causing a bit of energy increase from repel.

When do bonds form?

When potential energy is at a minimum.