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GCSE Chemistry > C2.2-2.3 > Flashcards

C2.2-2.3 Flashcards

1
Q

Physical property

A

Characteristic that cant be observed/measured

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2
Q

Physical properties of metals (left side)

A
  • shiny
  • high melting/boiling point
  • solid at room temp
  • malleable (bend without shattering) when solid
  • ductile (can be pulled into wires) when solid
  • good thermal/electrical conductors
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3
Q

Physical properties of non-metals (right side)

A
  • dull
  • low melting/boiling temps
  • half solid, half gas at room temp
  • brittle (shatter when hammered) when solid
  • non-ductile (snap when pulled) when solid
  • poor thermal/electrical conductors (insulators)
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4
Q

Chemical property

A

Characteristic of substance that can only be determined by studying its chemical reactions

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5
Q

Chemical properties of metals

A
  • lost electrons to form positive ions
  • don’t react with each other (mix to form alloys)
  • react with oxygen to produce metal oxides which dissolved in water to produce alkaline solutions
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6
Q

chemical properties of non-metals

A
  • gain electrons to form negative ions
  • react with each other to produce compounds that consist of molecules
  • react with oxygen to produce non-metal oxides which dissolve in water to produce acidic solutions
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7
Q

How do ionic compounds form?

A

A metal reacts with a non-metal

Electrons transferred from metal atoms to non-metal atoms so both more stable

  • metals become positive ions
  • non-metals become negative ions
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8
Q

Structure of ionic compound

A

contain positive & negative ions arranged in a regular way

= giant ionic lattice

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9
Q

Bonding of ionic compounds

A
  • ions held in place by ionic bonds, act in all directions

Ionic bonds = strong electrostatic forces of attraction between oppositely charged ions

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10
Q

Covalent bonds

A

Shared pair of electrons

Between 2 non-metal atoms when atoms get close enough to share electrons in outer shells = complete outer shells = stable

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11
Q

Simple molecules

A

Particle in which a few non-metal atoms are joined to each other by covalent bonds

(Hydrogen, oxygen, water, carbon dioxide)

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12
Q

Structure & bonding of simple molecules

A

Covalent bonds = strong electrostatic forces of attraction between nucleus of each bonded atom & shared electrons

Weak intermolecular forces between molecules

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13
Q

Giant covalent structure

A

Consists of many non-metal atoms joined by covalent bonds

& arranged in repeating regular pattern = giant lattice

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14
Q

Example of a giant covalent structure

A

Diamond (form of carbon)

= carbon atoms joined to 4 other carbon atoms by covalent bonds

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15
Q

Chemical formula of giant molecules (giant covalent structures) & why

A

Too many atoms

Use empirical formula

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16
Q

Monomers

A

Simple molecules

= consist of few non-metal atoms joined to each other by covalent bonds

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17
Q

Bonding of polymers

A
  • covalent bonds between individual polymer molecules

- weak intermolecular forces between polymer molecules

18
Q

Types of polymer

A
  • thermosoftening polymer: polymer chains relatively easy to separate

Thermosetting polymer: chains joined tougher by strong covalent bonds = cross linking, hard to separate

19
Q

Structure of metals

A

Atoms packed together in regular way
= forms giant metallic lattice

(Solid state at room temp, except mercury)

20
Q

Inner structure of metals which causes metallic bonds

A
  • Electrons leave outer shells of metal atoms
  • forming a sea of delocalised electrons around positively charged metal ions
  • delocalised electrons = free to move through structure of metal
21
Q

Metallic bonds

A

Strong electrostatic forces of attraction

between delocalised electrons & closely packed, positively charged metal ions

22
Q

How did Mendeleev’s periodic table differ from the modern-day one

A
  • had no noble gases (group 0)
  • has no transition elements
  • had gaps (left for elements to be discovered)
  • was ordered by atomic mass but now ordered by atomic number
  • didn’t have atomic number
  • swapped iodine & tellurium to reflect chemical properties
23
Q

What determines the chemical properties of an element

A

electronic structure of an element

24
Q

Group 1 properties

A
  • metals
  • very unreactive
  • electronic structure ends in 1
  • forms +1 ion
25
Q

Group 2 properties

A
  • metal
  • reactive
  • electronic structure ends in 2
  • forms +2 ion
26
Q

Group 7 properties

A
  • non-metal
  • very reactive
  • electronic structure ends in 7
  • forms -1 ion
27
Q

Group 0 properties

A
  • non-metal
  • very unreactive
  • full outer shell (electronic structure ends in 8)
  • doesn’t form ions (don’t react)
28
Q

Why did Mendeleev not think argon and helium were elements at first

A
  • both gases are inert (very unreactive, unable to form compounds)
  • he though elements should be able to react with other elements
29
Q

Who discovered the elements in group 0 and when

A

Ramsay

from 1894-1898

30
Q

Why can carbon form many different compounds

A

In group 4 = 4 electrons in outer shell = can form 4 covalent bonds

31
Q

Allotropes

A

Different forms of an element in the same state but with different atomic arrangements

32
Q

Allotropes of carbon

A
  • diamond
  • graphite
  • graphene
  • fullerenes (large family) : nanotube, buckyball
33
Q

Why do all allotropes have different properties even though they are all formed from carbon

A

Different structure & bonding

34
Q

Diamond properties

A
  • transparent
  • very hard
  • very high melting point
  • doesn’t conduct electricity (insulator)
35
Q

Diamond structure & bonding

A

Giant covalent structure
- each carbon atom covalently bonded to 4 other carbon atoms
Covalent bonds = strong

36
Q

why does diamond have a very high melting point & is very hard

A
  • has lots of strong covalent bonds, difficult to break
37
Q

why doesn’t diamond conduct electricity

A
  • all outer shell electrons in its atoms are shared when covalent bonds are formed
    = no delocalised electrons
38
Q

Graphite properties

A
  • soft
  • grey-black
  • conducts electricity
  • very high melting point
  • slippery
39
Q

Why does graphite conduct electricity

A

1 electron in outer shell of each atom not involved in bonding (only bonds to 3 electrons)
= delocalised electrons free to move through structure

40
Q

Why does graphite have a very high melting point

A
  • layered structure
  • atoms in each layer form interlocking hexagons like knots
  • many strong covalent bonds in layers
41
Q

Why is graphite slippery

A

weak forces between each layer = layers slide over each other easily

(Graphite tip on pencil)

42
Q

Graphite structure & bonding

A

Giant covalent structure

- each carbon atom covalently bonded to just 3 other carbon atoms

GCSE Chemistry (10 decks)

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