Chapter 3 Covalent Substances

Question 1

allotrope

Answer 1

different forms of the same element in which the atoms combine in different ways

Question 2

amorphous

Answer 2

a structure that has no consistent arrangement of particles

Question 3

asymmetrical molecule

Answer 3

a molecule in which the polar bonds are unevenly (or asymmetrically) distributed; the dipoles do not cancel and an overall molecular dipole is created

Question 4

combustion

Answer 4

a rapid reaction with oxygen accompanied by the release of large amounts of heat; also called burning

Question 5

covalent bond

Answer 5

the force of attraction formed when one or more pairs of electrons are shared between two nuclei

Question 6

covalent lattice

Answer 6

a three-dimensional lattice structure formed from covalently bonded non-metal atoms

Question 7

covalent layer lattice

Answer 7

an arrangement of atoms in a lattice in which there are strong covalent bonds between the atoms that have formed in a layer

Question 8

covalent network lattice

Answer 8

an arrangement of atoms in which there are strong covalent bonds between the atoms in all three dimensions

Question 9

diamond

Answer 9

a form of pure carbon that is the hardest naturally occurring substance

Question 10

diatomic molecule

Answer 10

a molecule formed from two atoms only

Question 11

dipole

Answer 11

the separation of positive and negative charges in a molecule

Question 12

dipole-dipole attraction

Answer 12

a form of intermolecular force that occurs between polar molecules where the partially positively charged end of one molecule is attracted to the partially negative charged end of another molecule

Question 13

dispersion forces

Answer 13

the force of attraction between molecules due to the temporary dipoles induced in the molecules; the temporary dipoles are the result of random fluctuations in the electron density

Question 14

double covalent bond

Answer 14

a covalent bond in which four electrons (two electron pairs) are shared

Question 15

electron density

Answer 15

the concentration of electrons that usually refer to the region around an atom or molecule

Question 16

electron group

Answer 16

a region of negative charge around an atom, which could be either different types of covalent bonds or a non-bonding pair

Question 17

electronegativity

Answer 17

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

Question 18

graphite

Answer 18

a form of carbon in which the carbon atoms are arranged in layers

Question 19

hydrogen bond

Answer 19

a type of intermolecular, dipole-dipole force where a hydrogen atom is covalently bonded to a highly electronegative atom such as oxygen, nitrogen or fluorine

Question 20

instantaneous dipole

Question 21

intermolecular force

Question 22

intramolecular bond

Question 23

Lewis structure

Question 24

molecular formula

Question 25

molecule

Question 26

non-bonding electron

Question 27

non-polar

Question 28

octet rule

Question 29

permanent dipole

Question 30

polar

Question 31

polarity

Question 32

polyatomic molecule

Question 33

pyramidal

Question 34

sublimation point

Question 35

single covalent bond

Question 36

structural formula

Question 37

symmetrical molecule

Question 38

temporary dipole

Question 39

tetrahedral

Question 40

trigonal planar

Question 41

triple covalent bond

Question 42

valence shell electron pair repulsion theory (VSEPR)