Chemical Bonding

Question 1

What is a compound?

Answer 1

2 or more different elements chemically combined

Question 2

How are atoms held together?

Answer 2

chemical bonds

Question 3

describe noble gases

Answer 3

contain 8 elements on outer shell and are generally unreactive

Question 4

what are the uses of helium

Answer 4

airships and balloons

Question 5

uses of argon

Answer 5

Used in lightbulbs (normal light bulbs) to stop imploding

Question 6

what is the octet rule

Answer 6

in forming compounds, atoms tend to achieve the electron configuration of a noble gas(8 electrons)

Question 7

what are the limitations of the octet rule

Answer 7

hydrogen, lithium, transition elements

Question 8

what is a valency

Answer 8

it is the no. of bonds an atom makes when it reacts

Question 9

what is a transition metal

Answer 9

it is one that forms at least one ion with a particularly filled sublevel

Question 10

facts about transition metals

Answer 10

they have variable valancy

form coloured compounds

used as catalysts

Question 11

name 2 types of bonding

Answer 11

ionic,convalant

Question 12

what is an ion

Answer 12

a charged atom/groups of atoms

Question 13

what is the charge of a cation

Answer 13

positive

Question 14

what is the charge of a anion

Answer 14

negative

Question 15

define ionic bonds

Answer 15

the attraction between oppositely charged ions in a compound

Question 16

why do ionic substances form substances

Answer 16

positive ions attract negative ions in all direcions

Question 17

what are the characteristics of ionic substances

Answer 17

• strong forces between ions means its very hard to –break up the lattice structure
• can conduct electricity when solid
• high melting/boiling points
• most dissolve in water
• solid at room temp

Question 18

examples of everyday ionic substances

Answer 18

table salt-Sodium Chloride (NaCl)

fluoridation in water-SodiumFlouride(NaF)

Question 19

When is a covalent bond formed?

Answer 19

when electrons are shared between atoms

Question 20

what are bonding pairs

Answer 20

shared electron pairs that form covalent bonds

Question 21

What are lone pairs?

Answer 21

electron pairs not involved in bonding

Question 22

How is a sigma bond formed?

Answer 22

formed by the head overlap of two orbitals (can be s/p orbitals)

Question 23

how is a pi bond formed

Answer 23

formed by sideways overlap of p-orbitals

Question 24

which is stronger sigma vs pi bonds

Answer 24

sigma bonds are stronger due to the fact that there is more overlap between orbitals

Question 25

what are the characteristics of ionic bonds

Answer 25

- transfer of electrons - ions formed - high melting/boiling point - usually solid at room temp - conducts electricity when molten

Question 26

what are the characteristics of covalent bonds

Answer 26

- sharing electrons - covalent bonds formed - low melting/boiling points - liquid/gaseous at room temp - deosnt conduct electricity

Question 27

what is In a single bond

Answer 27

one sigma

Question 28

what is in a double bond

Answer 28

one sigma, one pi

Question 29

what is in a triple bond

Answer 29

one sigma, two pi

Question 30

How are molecules formed?

Answer 30

Covalent bonds between two or more atoms.

Question 31

How is the shape of a molecule determined?

Answer 31

the arrangement of atoms

Question 32

what theory is used to figure up the arrangement of molecules

Answer 32

VSEPR- valance shell electron pair repulsion theory

Question 33

describe why the shape of lone and bonding pairs are disstorted(explain the basis for electron pair repulsion pair theory(i think))oooop

Answer 33

1. lone pair electrons are closer to the nucleus 2. due to this it they are closer together 3. collective nuclear charge pushes the bonding pairs further apart decreasing the bond angle+distorts the shape electrons in bonding pairs repel each other and want to be as far away as possible

Question 34

no. of bonding pairs around the central atom and angle of a linear molecule

Answer 34

2 atoms and 180 degrees

Question 35

no. of bonding pairs around the central atom and angle of a trigonal planar atom

Answer 35

3 atoms and 120 degrees

Question 36

no. of bonding pairs around the central atom and angle of a tetrehedral atom

Answer 36

4 atoms and 109.5 degrees

Question 37

what are lone pairs

Answer 37

Paired electrons that are not shared

Question 38

what is a molecule, no of bonding pairs,no of lone pairs, bod angle of a pyramidal molecule

Answer 38

NH3, 3, 1 ,107 degrees

Question 39

what is a molecule, no of bonding pairs,no of lone pairs, bod angle of a V-Shaped molecule

Answer 39

H20, 2 , 2, 104.5 Degrees

Question 40

What are non-polar covalent bonds?

Answer 40

equal sharing of electrons

Question 41

What are polar covalent bonds?

Answer 41

unequal sharing of electrons

Question 42

Define Elecronegativity

Answer 42

its the relative attraction an atom has for a shared pair of electrons in a single covelent bond

Question 43

what are the trends in the periodic table in terms of electromagnetically

Answer 43

Increase across the table=increase in nuclear charges/decreased atomic radius Decrease down the table=screening/increase atomic radius

Question 44

how do you predict the type of bond an atom has

Answer 44

check the electronegativity of the atoms involved calculate the difference in electronegativity

Question 45

what is the bond type of atoms with the electronegativity of non-polar covelant bonds

Answer 45

0-0.4 ex-H2,O2

Question 46

what is the bond type of atoms with the electronegativity of polar covelant bonds

Answer 46

0.41-1.7 example-H20

Question 47

what is the bond type of atoms with the electronegativity of Ionic bonds

Answer 47

greater than 1.7 example-NaCl

Question 48

a molecule that has polar bonds can be non-polar overall if its one of the following shapes

Answer 48

linear,trigonal planar, tetrahedral

Question 49

What is intramolecular force?

Answer 49

force within a molecule

Question 50

What is intermolecular force?

Answer 50

force between molecules

Question 51

what are the three types of molecular bonding

Answer 51

Van Der Waal Dipole-Dipole Hydrogen bonding

Question 52

What are Van der Waals forces?

Answer 52

weak forces of attraction between temporary dipoles

Question 53

What are dipole-dipole forces?

Answer 53

forces of attraction between negative polar of one molecule and the positive pole of another

Question 54

What are hydrogen bonds?

Answer 54

occurs in molecules where a hydrogen atom is bonded to nitrogen,oxygen,fluorine. the hydrogen carries a positive charge and is attracted to the electronegative in another molecule