Covalent Bonding !!

What is a covalent bond?

a bond formed when two positive nuclei are held together by their common attraction for a shared pair of electrons

What type of elements form covalent bonds?

nonmetals

Covalent bonds are __________ bonds

strong

Why do elements form covalent bonds?

in order to have a full outer shell of electrons

What is shared in a covalent bond?

electrons

What do covalent bonds form?

molecules

What is a molecule?

group of atoms held together by covalent bonds

What is a diatomic molecule?

a molecule that contains only two atoms

What is a diatomic element?

elements that exist as a diatomic molecule

What are the 7 diatomic elements?

hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, iodine

More than one bond can be formed, what does this lead to?

double and triple bonds

What do the shape of covalent molecules depend on?

the number of bonds and the orientation of these bonds around the central atom

The shape of a molecule that has two covalent single bonds and no lone pairs on the central atom is

linear

The shape of a molecule that has two covalent single bonds and two lone pairs on the central atom is

angular

The shape of a molecule that has three single covalent bonds and one lone pair on the central atom is

trigonal pyramidal

The shape of a molecule whose central atom has four pairs of bonding electrons is

tetrahedral

Covalent substances can form either

discrete molecular or giant network structures

What is a covalent molecular substance?

simple molecules held together by weak forces of attraction

Examples of covalent molecular

water,ammonia,iodine

What state is a covalent molecular substance?

solids,liquids or gases at room temperature

Covalent molecular substances have ______________ within the molecules and only ______________ between the molecules

strong covalent bonds, weak attractions

Why do covalent molecular substances have ___ melting and boiling points?

low, because only little energy is needed to separate the weak attraction between the molecules

Why do covalent molecular substances not conduct electricity?

because they do not have charged particles which are free to move

Covalent molecular substances which are insoluble in water may _______________

dissolve in other solvents

What is a covalent network substance?

A giant structure where atoms are covalently bonded together

Examples of covalent networks

Diamond, graphite, silicon dioxide

What state is a covalent network substance?

solid

Covalent network structures have a _____________ within one ___________

network of strong covalent bonds,giant structure

Why do covalent network substances have ____ melting and boiling points?

high, because the network of strong covalent bonds is not easily broken

Why do covalent network substance not conduct electricity?

because they do not have charged particles which are free to move

Why can graphite conduct electricity?

because of the delocalised electrons along its layers.

covalent networks ______ dissolve

do not