Unit 1, Topic 3 - Bonding and Structure Flashcards

1
Q

What types of substances usually form together to make ionic compounds?

A

Metal and non-metal

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2
Q

Describe ionic bonding

A

It is an electrostatic force of attraction between oppositely charged ions.

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3
Q

What can be said about the strength of ionic bonds?

A

They are strong

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4
Q

Why do atoms gain or lose electrons?

A

They are more stable with a full outer shell of electrons. When forming compounds atoms tend to have stable electron arrangement.

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5
Q

How do you work out how many electrons a metal loses when it forms an ion?

A

A metal loses electrons equal to the number of electrons in the outer shell.

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6
Q

A metal loses electrons equal to the number of electrons in the outer shell.
Why do metal ions do this?

A

They are more stable with a full outer shell of electrons.

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7
Q

What always happens when metal atoms form ions?

A

They lose electrons to form positive ions.

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8
Q

Write an equation to show how aluminium ions are formed from aluminium atoms.

A

Al —> Al 3+ + 3e-
2,8,3 2,8

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9
Q

What happens to non-metal atoms when they form ions?

A

They always gain electrons to become negative ions.

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10
Q

How do you work out how many electrons a non-metal atom gains when it forms an ion?

A

The number of electrons gained is the same as the number of electrons needed to fill the outer shell.

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11
Q

Know how to write nuclide notation for ions. E.g. How would you write the nuclide notation for a chloride ion with mass number 35?

A

35
Cl-
17

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12
Q

Know how to work out the number of protons, neutrons and electrons when given the nuclide notation of an ion. E.g. 27
Al 3+
13

A

protons+13
neutrons+14
electrons=10

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13
Q

What type of substances have metallic bonding?

A

Metals

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14
Q

Describe metallic bonding.

A

Electrostatic attraction between positively charged atom cores or ions and delocalised electrons.

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15
Q

What can be said about the strength of a metallic bond?

A

It is strong

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16
Q

What type of elements usually form covalent compounds?

A

Non-metal atoms

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17
Q

What is a covalent bond?

A

A shared pair of electrons

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18
Q

What holds the atoms together in covalent bonding?
(be able to draw diagrams)

A

The shared pair of electrons is attracted to both positive nuclei.

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19
Q

Be able to draw diagrams to show howthe outer electrons are shared in elements and compounds to from covalent bonds.

A

See notes and slides.

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20
Q

What is the formula for an oxygen molecule? How many bonds are there between atoms?

A

O2-2 shared pairs of electrons (we write the 2 smaller and at the bottom of the O.

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20
Q

What is a diatomic molecule?

A

A molecule that contains 2 atoms

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21
Q

What is a molecule?

A

A group of atoms held together by covalent bonds.

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22
Q

What are the 7 elements that exist as a diatomic molecule?

A

H2, O2, N2, F2, Cl2, Br2, I2

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22
Q

Which of the following molecules are diatomic?
HCl, H2O,NH3, CO, CO2

(be able to identify compounds that exist as diatomic molecules)

A

CO and HCl

23
Q

What shape are diatomic molecules?

A

Linear

23
Q

Look at LI 24-27

A

for drawing the shape of atom molecules.

23
Q

What is meant by a discrete molecular substance?

A

One that exists with separate molecules.

24
Q

What do most covalent substances exist as?

A

Discrete covalent molecules

25
Q

What type of bonding is found in a molecule?

A

Covalent

26
Q

Are covalent bonds inside molecules strong?

A

Yes, they are strong

26
Q

Are the bonds (forces of attraction) between molecules strong?

A

No, they are weak

26
Q

What term is used to describe bonds between molecules?

A

Intermolecular bonds/forces of attraction

27
Q

What does the formula of discrete covalent substances tell you?

A

The actual number of atoms in the molecule.

27
Q

Describe what is meant by a covalent network.

A

A giant structure where atoms are covalently bonded together.

28
Q

What information does the formula of a covalent network give you?

e.g SiO2

A

Contains the simplest ratio of atoms of each element.

e.g for every Si atom there are 2 0 atoms.

29
Q

Name 2 elements with a covalent network structure?

A

Silicon and Carbon (graphite and diamond)

30
Q

Name 2 compounds with a covalent network structure?

A

Silicon dioxide and Silicon carbide.

31
Q

What type of structure do ionic compounds have?

(look at diagram for LI 37)

A

Ionic compounds consist of a lattice of oppositely charged positive and negative ions. An ionic crystal lattice.

32
Q

What information do you get from the formulae of an ionic compound?
e.g MgCl2

A

The ratio of each ion present in the ionic crystal lattice.

33
Q

What is an electric current?

A

A flow of charged particles

34
Q

What charged particles can carry a current?

A

Freely moving/ Delocalised electrons OR ions.

35
Q

Why do metals and carbon (graphite) conduct electricity?

A

Metals and graphite both have delocalised electrons in their structure which are free to move.

36
Q

Why do covalent compounds not conduct electricity?

A

Covalent compounds consist of molecules that are uncharged, they contain no charged particles (either ions or delocalised electrons to carry a current.)

37
Q

In what state will ionic compounds conduct?

A

Ionic compounds don’t conduct in the solid state but do when dissolved in water or when molten.

38
Q

Why do ionic compounds conduct when dissolved or molten but not when solid?

A

The ions are free to move when molten or dissolved but they are not free to move when solid as they are held in a lattice structure.

39
Q

Why do metals have high melting and boiling points?

A

the delocalised electrons are attracted to many surrounding positive ion cores.

40
Q

Why do ionic compounds have high melting and boiling points?

A

there is a strong electrostatic force of attraction between positive and negative ions.

41
Q

Why do covalent network structures have high melting and boiling points?

A

the mutual attraction of the shared pair of electrons to both positive nuclei.

42
Q

Why do discrete covalent molecular substances have low melting and boiling points?

A

Only weak force of attraction between molecules are broken when these substances melt/boil. The strong covalent bonds in the molecule are NOT broken.

43
Q

What can be said of the solubility of ionic substances in water?

A

They are usually soluble.

44
Q

Covalent substances may or may not soluble in water. What can those that are not be dissolved in?

A

Other covalent solvents such as hexane.

45
Q

What do metals and non-metals usually form?

A

ionic bonds

46
Q

How many non-metals usually form covalent bonds?

A

Two or more

47
Q

What is an element?

A

A substance that is made of only one type of atom. A chemical element is a chemical substance that cannot be broken down into other substances.

48
Q

What term is used to describe bonds between molecules?

A

“intermolecular forces are weak”
Covalent bonds inside molecules are strong whereas the bonds (forces of attraction) between molecules are weak.

49
Q

What are some properties of ionic compounds?

A

High melting and Boiling Points, conduct in the liquid state ie dissolved in water, they do not conduct electricity in the solid state

50
Q

Name the shape of some 3 atom molecules (containing 2 bonds).

A

Angular/bent

51
Q

Name the shape of some 4 atom molecules (containing 3 bonds).

A

Pyramidal

52
Q

Name the shape of some 5 atom molecules (containing 4 bonds).

A

Tetrahedral