Chemical Changes and Structures

Question 1

bonding electrons

Answer 1

shared pairs of electrons from both atoms forming the covalent bond

Question 2

chemical bonding

Answer 2

the mechanism by which atoms are held together

Question 3

chemical structure

Answer 3

the way in which atoms, ions or molecules are arranged

Question 4

covalent bond

Answer 4

formed when two atoms share electrons in their outer shell to complete the filling of that shell

Question 5

covalent radius

Answer 5

half the distance between the nuclei of two bonded atoms of an element

Question 6

delocalised

Answer 6

electrons in metallic bonding which are free from attachement to any one metal ion and are shared amongst the entire structure

Question 7

diatomic

Answer 7

moelcules with exactly two atoms

Question 8

dipole

Answer 8

an atom or molecule in which a concentration of positive charges is separated from a concentration of negative charges

Question 9

electronegativity

Answer 9

a measure of the attraction that an atom involved in a bond has for the electrons of the bond

Question 10

fullerene

Answer 10

molecules of carbon constructed of 5- and 6- membered rings combined into hollow spherical structures

Question 11

hydrogen bonds

Answer 11

intermolecular forces between molecules containing a hydrogen atom bonded to an atom of a strongly electronegative element such as fluorine, oxygen or nitrogen, and a highly electronegative atom on a neighbouring molecule

Question 12

intermolecular forces

Answer 12

are those which attract atoms and molecules together (also known as van der Waals forces)

Question 13

ion-electron equation

Answer 13

a half-equation, either oxidation or reduction, which in combination with the opposite type, can be part of a complete redox equation

Question 14

ionic bond

Answer 14

a bond between atoms with substantially different electronegativity, which results in the formation of positive and negative ions (with the negative ion having the higher electronegativity)

Question 15

ionisation energy

Answer 15

the energy required to remove one mole of electrons from one mole of atoms in the gaseous state

Question 16

isoelectronic

Answer 16

having the same number of electrons

Question 17

lattice

Answer 17

a regular 3D arrangement of particles in space

Question 18

London dispersion forces

Answer 18

the forces of attraction which result from the electrostatic attraction between temporary and induced dipoles caused by movement of electrons in atoms and molecules

Question 19

miscible

Answer 19

fluids which mix or dissolve in each other in all propotions

Question 20

non-polar / pure covalent bond

Answer 20

bond between atoms with the same or very similar electronegativity which results in an equal sharing of the bonding electrons between the atoms

Question 21

oxidation

Answer 21

a loss of electrons by a reactant in any reaction

Question 22

oxidising agent

Answer 22

a substance which accepts electrons

Question 23

periodicity

Answer 23

the regular recurrence of similar properties when the elements are arranged in order of increasing atomic number

Question 24

permanent dipole to permanent dipole interactions

Answer 24

intermolcular forces of attraction which exist between polar molecules

Question 25

polar covalent bond

Answer 25

a bond between atoms of different electronegativity, which results in an uneven distribution of electrons and a partial charge along the bond

Question 26

properties

Answer 26

the physical and chemical characteristics of a substance

Question 27

reducing agent

Answer 27

a substance which donates electrons

Question 28

reduction

Answer 28

a gain of electrons by a reactant in any reaction

Question 29

viscosity

Answer 29

the resistance to flow that is exhibited by liquids

Question 30

screening/shielding effect

Answer 30

describes how the inner electrons reduce the attraction between the nuclear charge and bonding electrons

Question 31

bonding continuum

Answer 31

the spectrum of bonding from pure covalent to ionic

Question 32

monatomic

Answer 32

single, unattached atoms which are stable due to full outer energy levels

Question 33

like dissolves like

Answer 33

a general rule about solubility, since polar molecules dissolve in polar solvents, and non-polar molecules dissolve in non-polar solvents