Chem 2 - Electrons And Bonding/ Shapes Of Molecules And Intermolecular Forces

Front 1

Define Orbital

Back 1

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

Front 2

Shape of an S orbital

Back 2

Sphere

Front 3

Shape of a P orbital

Back 3

Dumb bell

Front 4

Define principal quantum number

Back 4

The shell number or energy level of an atom

Front 5

How many electrons can be held in each shell?

Back 5

1 - 2 electrons

2 - 8 electrons

3 - 18 electrons

4 - 32 electrons

Front 6

Define sub shell

Back 6

A group of orbitals of the same type within a shell

Front 7

Explain the blocks of a periodic table

Back 7

Block elements (such as S block) have there highest energy electrons in the subshell named. (So s block elements like Sodium have their highest energy electrons in an s sub shell)

Front 8

Define an ionic bond

Back 8

An electrostatic attraction between ions of opposite charge

Front 9

Difference between cations and anions

Back 9

Cations are when metal atoms lose electrons and become positive ions

Anions are when non metal atoms gain electrons and become negative ions

Front 10

What is an ionic bond?

Back 10

It is the electrostatic attraction between ions of opposite charge.

Front 11

State the 3 properties of ionic compounds

Back 11

● high melting and boiling points

● soluble in polar solvents, insoluble in non polar solvents

● can conduct electricity when molten or dissolved

Front 12

A covalent bond

Back 12

A shared pair of electrons where the atoms are held together by strong electrostatic bonds between the nuclei of each bonding atom and the electrons in the bonding pair

Front 13

What is a molecule?

Back 13

A small unit of two or more atoms covalently bonded together

Front 14

What is a lone pair?

Back 14

A pair of electrons not involved in the covalent bonding

Front 15

What is a dative covalent bond?

Back 15

A shared pair of electrons in which both of the electrons in the shared pair come from one of bonding atoms only

Front 16

What elements are able to have more than 8 electrons in their outer shell?

Back 16

Éléments in period 3 of the periodic table because they have access to the D sub shell

Front 17

What is bond enthalpy?

Back 17

It is the measurement of covalent bond strength. The larger the value of this, the stronger the covalent bond

Front 18

What two properties determine the strength of an ionic bond?

Back 18

The size and charge of the ions involved

● smaller ions form stronger ionic bonds because the electrostatic attraction from the nucleus is stronger due to a smaller radius and less electron shielding (atoms in a higher period would therefore make stronger ionic bonds)

● more highly charged atoms form stronger ionic bonds

Front 19

Explain the valence shell electron pair repulsion theory

Back 19

● valence shell electrons are the outermost electrons

● the electron pairs in the valence repel each other as far apart as possible. Lone pairs gave a stronger repulsion

● this determines the shape of the molecule

Front 20

What is the shape and angle of a molecule with 2 bonding pairs?

Back 20

Linear. 180°

Front 21

What is the shape and angle of a molecule with 3 bonded pairs?

Back 21

Trigonal planar. 120°

Front 22

What is the shape and angle of a molecule with 4 bonded pairs

Back 22

Tetrahedral. 109.5°

Front 23

What is the shape and angle of a molecule with 6 bonded pairs?

Back 23

Octahedral. 90°

Front 24

What is the shape and angle of a molecule with 3 bonded pairs and 1 lone pair?

Back 24

Pyramidal. 107°

Front 25

What is the shape and angle of a molecule with 2 bonding pairs and 2 lone pairs?

Back 25

Non linear. 104.5°

Front 26

What is the shape and angle of a molecule with 2 double bonds and 1 lone pair? (E.g. SO2)

Back 26

Non linear. 120°

Front 27

What is electronegativity?

Back 27

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

Front 28

What is the shape and structure of a SO4^2- ion?

Back 28

Front 29

What is a polar bond?

Back 29

A covalent bond between atoms with different electronegativities with positive and negative partial charges on the bonded atoms

Front 30

What causes a polar bond?

Back 30

Different electronegativity values causing the shared pair of electrons to be shared unequally between the two bonding atoms

Front 31

What is a dipole

Back 31

The separation of partial charges in a molecule

Front 32

Is a symmetrical molecule polar or non polar?

Back 32

Non polar because the charges cancel each other out

Front 33

What are intermolecular forces?

Back 33

They are the weak attractive forces between molecules

Front 34

What are the three types of intermolecular forces?

Back 34

● induced dipole dipole interactions (London forces)

●permanent dipole dipole interactions

● hydrogen bonds

Front 35

What causes hydrogen bonds to occur?

Back 35

● when a H atom Is bonded to an electronegative atom (O, N, F )in one molecule

● a lone pair of an electronegative atom in a different molecule

Front 36

What are the anomalous properties of water?

Back 36

● ice is less dense than water

● higher melting point than expected

Front 37

Explain solubility of simple molecules

Back 37

● in general simple molecules have weak dipoles and so are soluble in non polar solvents (but Insoluble in water)

● highly polar molecules are soluble in water because they can interact with the dipoles in water molecules

Front 38

How are London forces created?

Back 38

● movement of electrons produces a changing dipole, resulting in an instantaneous dipole

● instantaneous dipole induces a dipole in a neighbouring molecule

● induces dipole induces another dipole etc... then they attract one another

Front 39

Isoelectronic

Back 39

The same number of electrons