Electrons and bonding (definitions)

Question 1

Sub-shell def

Answer 1

A sub-division of an energy level. Sub-shells may be s, p, d or f sub-shells.

Question 2

orbital def

Answer 2

A region of a sub-shell that contains a maximum of 2 electrons with opposite spin

Question 3

ionic bond def

Answer 3

the electrostatic attraction between positive and negative ions

Question 4

ionic compound

Answer 4

compound made from oppositely charged ions

Question 5

What makes ionic bonds stronger, what does this result in

Answer 5

bigger charges higher melting points

Question 6

when do ionic compounds conduct electricity and why

Answer 6

when molten or dissolved, not solid ions free to move and carry charge

Question 7

whats the solubility of ionic compounds

Answer 7

soluble in polar solvents e.g. water.

Question 8

whats the metling/boiling points of ionic compounds (high or low)

Answer 8

very high. Giant ionic lattices held by strong electrostatic forces. Loads of energy needed to overcome forces.

Question 9

covalent bond def

Answer 9

strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 10

dative covalent bond (coordinate bond) def

Answer 10

a covalent bond formed when 1 atom provides both of the shared electrons.

Question 11

how are dative covalent bonds represented

Answer 11

with arrow coming from where pair of electrons is coming from

Question 12

electron shell def

Answer 12

a region of an atom with a fixed energy that contains electrons orbiting the nucleus

Question 13

electron shell repulsion theory

Answer 13

in a molecule lone pair/lone pair bond angles are biggest lone pair/bonding pair angles are second biggest bonding pair/bonding pair angles are smallest

Question 14

electronegativity def

Answer 14

ability of an atom to attract the bonding electrons in a covalent bond

Question 15

permanent dipole - dipole interactions

Answer 15

intermolecular forces that exist because the difference in electronegativities in a polar bond causes weak electrostatic forces of attraction between molecules

Question 16

what E.N difference is there for non-polar covalent bonds

Answer 16

<0.4

Question 17

what E.N difference is there for ionic but still mainly covalent

Answer 17

0.4 - 2.0

Question 18

what E.N difference is there for mainly ionic

Answer 18

2>

Question 19

Name the 3 tyoes of intermolecular force

Answer 19

induced, permanent hydrogen

Question 20

induced dipole - dipole (London forces) def

Answer 20

type of intermolecular force caused by temporary dipoles, which causes all atoms and molecules to be attracted to eachother.

Question 21

what increases strength of london forces

Answer 21

larger molecules (larger electron clouds) larger S/A

Question 22

what elements can hydrogen occur with

Answer 22

fluorine, nitrogen, oxygen

Question 23

why is ice less dense than water

Answer 23

hydrogen bonds are long, hydrogen bonds broken when ice is melted, so less hydrogen bonds in water than ice. So molecules on average molecule in ice will be further apart than in liquid. Makes ice less dense. Unusual

Question 24

can covalent compounds conduct electricity and why

Answer 24

no overall dipole is unchanged

Question 25

whats the melting/boiling points of covalnet comapounds and why

Answer 25

intermolecular forces weak so little energy needed to break them. low boiling/melting point.

Question 26

whats the solunility of covalent compounds and why

Answer 26

compounds with hydrogen bonds can form H bonds with water making them soluble. Molecules that aren’t polar will be insoluble.

Question 27

main factor that determines boiling point

Answer 27

strength of london forces (unless H bonds can be made)