2.5 Electrons and Bonding ✓

shell no. or energy lvl

2

8

18

32

$2n^2$

region around the nucleus that can hold up to 2 electrons with opposite spins

sphere

1, 1

radius

2, 3

dumb-bell

90 degrees between each

further

3, 5

4, 7

groups of orbitals that are the same type within a shell

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 4d, 4f

orbitals fill in order of increasing energy

to counteract repulsion between negative charges

one electron occupies each orbital before pairing, preventing repulsion between paired electrons until no further orbital available at same energy level

$1s^2 2s^2 2p^6 3s^1$

$[Ne]3s^1$

positive ions formed when atoms lose electrons

negative ion formed when atoms gain electrons

-divided into blocks corresponding to their highest energy sub shell

sub-shell with highest energy

before, because the 4s energy level is lower than 3d

before, because once filled the 3d energy level falls below the 4s energy level

electrostatic attraction between positive and negative ions

$Al^{3+}$

$NH_4^+$

$NO_3^-$

$SO_4 ^{2-}$

each ion attracts oppositely charged ions in all directions

solid, insufficient energy to overcome strong electrostatic forces of attraction between oppositely chrged ions in giant ionic lattice

yes

stronger attraction so more energy needed

polar solvents, as can break down lattice and surround each ion in solution

large charges mean ionic attraction may be too strong for water to break down lttice structure, making compound not very soluble

-ionic lattice must be broken down
-water molecules must attract and surround ions

-relative strengths of attractions within giant ionic lattice
-attractions between ions and water molecules

no, ions fixed position in giant ionic lattice so no mobile charge carriers

yes, solid ionic lattice broken down so ions free to move as mobile charge carriers

strong electrostatic attraction between shared pair of electrons and nuckei of bonded atoms

-non metallic elements
-compounds of non metallic elements
-polyatomic atoms

both nuclei

acting solely between shared pair of electrons and muclei of 2 bonded atoms resulting in a molecule

paired electrons that are not covalently shared

no

covalent bonds resulting in more than 8 electrons in the outer shell

from n=3 shell, when d-sub-shell available for expansion

electrostatic attraction is between 2 shared pairs of electrons and nuclei of bonding atoms

electrostatic attraction is between 3 shared pairs of electrons and nuclei of bonding atoms

coordinate bond

covalent bond where shared pair of electrons supplies by one of bonding atoms only

lone pair

arrow pointing towards atom being supplied with electrons

measurement of covalent bond strength (larger value= stronger bond)

electron pairs repel eachother so arranged as far apart as possible, this minimises repulsion so holds definitive shape

strong

weak interactions

-induced dipole-dipole interactions (London forces)
-permanent dipole-dipole interactions
-hydrogen bonding

physical properties like mp and bp

identity and chemical reactions of molecules

yes

1) movement of electrons produces an instantaneous dipole
2) instantaneous dipole induces dipole in neighboring molecule
3) induced dipole induces further dipoles on neighboring molecules which then attract each other

larger

greater London force

-intermolecular forces are greater with more electrons (due to it causing a greater impact with London forces)
-more energy is required to overcome greater intermolecular forces

Both have london forces but H-Cl also has permanent dipole interaction meaning more energy is required to overcome intermolecular forces in H-Cl, giving it a higher bp

small unit containing definite number of atoms with definite molecular formula

low

regular structure called a simple molecular lattice

-molecules held in place by weak intermolecular forces
-atoms within molecules bonded together by strong covalent bonds

Covalent

-ionic/ covalent bonds
-hydrogen bonds
-dipole-dipole forces
-London forces

Electron deficient atoms weakly attracted to electron rich atoms of other molecules

larger

yes
-intermolecular forces form between molecule and solvent
-interactions weaken intermolecular forces in simple molecular lattice
-intermolecular forces break and compound dissolves

no
-little interaction between molecules in lattice and solvent molecules
-intermolecular bonding within polar solvent too strong to be broken

yes as their molecules attract each other

-strength of dipole
-hard to predict

have polar (eg O-H) and non polar (eg carbon chain) parts

no, so nothing can complete electrical circuit making it a non-conductor

polar, containing electronegative atoms (often oxygen) that can interact with water

non-polar, comprised of carbon chain

Permanent dipole-dipole interaction

-hydrogen atom attached to electronegative atom
-electronegative atom with lone pair of electrons

dashed line

floats on tops of water forming an insulating layer and preventing the water from freezing solid

hydrogen bonds extend outwards, holding water molecules slightly apart + forming open tetrahedral lattice full of holes

-holes in open lattice structure decrease density of ice
-when melting, ice lattice collapses and molecules move closer together making it denser

energy needed to break hydrogen bonds not just london forces

hydrogen bonds break completely

their rigid arrangement is broken

relatively high surface tension and viscosity