Module 2 Chapter 2 Flashcards by Jennifer Song

What is the formula for the max. number of electrons in a shell n?

2n^2

How well did you know this?

Not at all

Perfectly

What are atomic orbitals?

Regions within an atom that can hold up to two electrons , with opposite spins

How well did you know this?

Not at all

Perfectly

What can electrons be thought of as being?

Being a cloud of negative charge with the shape of the orbital

How well did you know this?

Not at all

Perfectly

Name the four orbitals

S, P, D, F

How well did you know this?

Not at all

Perfectly

No. of electrons in each orbital

S- 2
P-6
D-10
F-14

How well did you know this?

Not at all

Perfectly

Shape of s and p orbitals

S is spherical
P is dumb bell shape

How well did you know this?

Not at all

Perfectly

Where is the highest energy level?

Further away from nucleus

How well did you know this?

Not at all

Perfectly

Why does 4s fill before 3d?

4s energy level is below the 3d energy level

How well did you know this?

Not at all

Perfectly

What does the 4s sub-shell do before the 3d sub-shell?

Fills and empties

How well did you know this?

Not at all

Perfectly

why does certain elements in the periodic table classified as p-block elements

elements in the p block have their outer electron in p orbitals/subshells

How well did you know this?

Not at all

Perfectly

what is ionic bonding

the net electrostatic attrations between oppositely charged ions

How well did you know this?

Not at all

Perfectly

whats the charge of cations and anions

cations- +ve
anions- -ve

How well did you know this?

Not at all

Perfectly

what structure are ions arranged

giant lattice- cations and anions alternate in structure

How well did you know this?

Not at all

Perfectly

why is the bp, mp high for ionic compounds

require lots of energy to separate ions since there is strong electrostatic attraction between oppositely charged ions

How well did you know this?

Not at all

Perfectly

why does ionic compounds dissolve in water like nacl

water is polar and water molecules attract and bond to (na+ and cl-) ions, weakening ionic bonding and will surround them when lattic breaks down

How well did you know this?

Not at all

Perfectly

what happens to solubility as ionic charge increases

solubility decreases

How well did you know this?

Not at all

Perfectly

define covalent bonding

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

How well did you know this?

Not at all

Perfectly

what are lone pairs

paired electrons that are not shared

How well did you know this?

Not at all

Perfectly

what is the expanded octet

the unpaired electrons pair up
and max no. of electrons that can pair up is same as no. of electrons in outer shell
only possible from n=3 shell

How well did you know this?

Not at all

Perfectly

eg of expanded octet

SF6- 6 unpaired electrons from sulphur are paired so now contains 12 electrons

How well did you know this?

Not at all

Perfectly

what is a dative bond

pair of electrons which were both donated by one of the atoms

How well did you know this?

Not at all

Perfectly

whats the charge of ammonium ion

NH4+

How well did you know this?

Not at all

Perfectly

whats the charge of nitrate and nitrite

NO3-
NO2-

How well did you know this?

Not at all

Perfectly

whats the charge of hydrogencarbonate

HCO3-

How well did you know this?

Not at all

Perfectly

whats the charge of carbonate

CO3 2-

whats the charge of sulphate and sulphite

SO4 2- SO3 2-

whats the charge of dichromate

Cr2 O7 2-

define giant ionic lattice

a 3d structure of oppositely charged ions held together by strong ionic bonds

why is giant ionic lattice solid at room temp, therefore high bp and mp

insufficient energy to overcome the strong electrostatic force of attraction between opp. charged ions

why does giant ionic lattice conduct electricity when molten or aq

ions become mobile charge carriers

define covalent bond

the overlap of atomic orbitals, each containing one electron, to give a shared pair of electrons

what is a molecule

smallest part of a covalent compound that can exist retaining the chemical properties of the compound

why do some elements exist as a diatomic particle in nature

far more stable in bonded pairs than on their own

how is a dative bond written

an arrow A--> B

what is bond enthalpy

measure of covalent bond strength

what are electron pairs

clouds of negative charge so there is mutual repulsion between them, forcing them as far apart as possible

what does the shape of molecules depend on

the number of electron pairs around the central atom

which electron pairs repel the most

lone pairs repel more than bonding pairs

for every lone pair what happens to the bond angle

subtract 2.5 from orginal bond angle

whats the shape when theres 2 electron pairs and their bond angle

linear- 180

whats the shape and bond angle when theres 3 electron pairs

trigonal planar- 120

whats the shape and angle when theres 4 electron pairs

tetrahedral- 109.5

whats the shape and angle when theres 5 pairs

octahedral- 90

define electronegativity

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

due to electronegativity what happens to the electron density

not shared equally between two different elements

how does nuclear charge affect electronegativity

the more protons the stronger the attraction from nucleus to the bonding pair of electrons

how does atomic radius affect electronegativity

the close the bonding electrons to the nucleus the stronger the attraction

how does shielding affect electronegativity

the less shells shielding the bonding electrons the stronger the attraction

whats the trend for electronegativity DOWN a group

decreases- atomic radius increase more shielding so less attraction

whats the trend for electronegativity ACROSS a period

increases- atomic radius decrease more nuclear charge same shielding so stronger attraction

what is pure covalent bond/ non-polar bond

when 2 atoms are identical, electrons are shared equally (same electronegativity)

what is polar covalent bond

bond between different atoms the more electronegative atom will have greater share of electrons

whats a dipole

the separation of opposite charges

what is the dipole in a polar covalent molecule called

permanent dipole

what molecule is it if polar bonds are arranged symmetrically

dipoles cancel out so no overall dipole and is non-polar molecule

what molecule is it if polar bonds are arranged asymmetrically

charge will be arranged unevenly so have an overall dipole and is polar molecule

order the bond types by strongest to weakest

single covalent bond H bonds permanent dipole-dipole forces induced dipole-dipole forces ( london forces)

what is permanent dipole-dipole interactions

weak attractive force (electrostatic attration) between permanent dipoles in neighbouring polar molecules

what is london forces

weak attraction caused by uneven distribution of electrons in an atom due to random electron movement- creates a (temporary) instantaneous dipole which induces a dipole in neighbouring atoms

whats the solubility of a non-polar simple molecule

soluble in non-polar substance since interactions weaken intermolecular forces insoluble in polar substance since intermolecular bonding within polar solvent is too strong to be broken

whats the solubility of polar simple molecule

polar covalent substance dissolve in polar solvent since molecules attract each other also depends on strength of dipole

what is H bond

attraction between a lone pair on a highly electronegative atom in one molecule and a H atom in a diff molecule

which atoms form largest dipole with H bonds

N, O, F since they are highly electronegative due to nuclear charge and small size

when ice melts or boils which bond is broken

H bonds but not covalent bonds

why is bp of water much higher than expected

due to H bonds between the O of one molecule and H of another

how many H bonds can each water molecule form

2 H bonds ( in ice each 0 is surrounded by a tetrahedron of H atoms)