LO 13 and 12 intro to bonding

Is hydrogen from a stable or unstable bond?

stable

What kind of bond does helium form?

helium forms no bonds

Why is there a different in strength?

LDFs and covalent bonds have similar causes- electrostatic attraction of the electrons of one atom to the nucleus of another.

What is the specific reason for difference in strength? What are the differences?

the magnitude of attraction and how electrons are arranged in the new species. (which is formed by the interaction)

Describe a covalent bond 1.

1. valence electrons from one atom become attracted to the other nucleus.

Describe a covalent bond 2.

each nucleus is attracting both electrons

What is bond length?

the most stable distance between atoms- the lowest potential energy

What’s happens when bond form?

energy is released to the surroundings

Describe Molecular orbital theory (band theory )

• atomic orbital from separate atom mix to form new molecular orbitals in the molecule.

What ideas are MOT based on? 1

1. Electrons are waves and are not specifically “located” anywhere

What ideas are MOT based on? 2

2. -orbitals are calculated regions of electron density and probability

What ideas are MOT based on? 3

3, because electrons are waves when their electrons mix they can interact constructively and destructively 

what is formed when atomic orbitals combine destructively?

forms a molecular orbital of higher energy

what is formed when atomic orbitals combine constrctively?

forms a molecular orbital of lower energy

The total number of electrons formed equals what?

total number of atomic orbitals being combined

bonding orbitals are of what kind of energy?

lower in energy

electrons in bonding orbitals make the species stable or unstable?

more stable

anti bonding orbitals are what what energy?

higher energy

electrons in anti bonding orbitals make the species stable or unstable?

more unstable

bonding in metals

atomic orbitals combine with each other to form molecular orbitals

relationship between MOs and energy distance

as the MO increases the, the energy distance between them decreases

what happens when the tuber of MO increases

they form band soft MOs- of almost continuous energy

movement of electrons between the extended network of MOs

can move freely, and therefore also over the whole system

because metals can move freely around…

metals conduct electricity

because atoms can move with respect to one another…

there is still space between them, metals are malleable

the metal interacts with the light of many wavelengths so…

the metals appears white or colorless( silver)

what doe the magnitude of the melting and boiling point provide

an estimate of the strength of the attractive interactions between particles.

What kinds of interactions
and/or bonds must be
overcome in order to melt
elements with lower mp/bp?

LDFs.

What kinds of interactions
and/or bonds must be
overcome in order to melt
elements with higher mp/bp?

metallic and covalent

properties of diamond

high mp

brittle

doens’t conduct electricity

properties of graphite

High mp

soft

conducts electrify