Chemistry Flashcards
1
Q
Density
A
How easily it sinks
2
Q
Boiling point
A
The temperature the substance changes from a liquid to a gas
3
Q
Melting point
A
The temperature where it changes from a solid to liquid
4
Q
Features of a pure substance
A
Fixed melting point
Fixed boiling point
Contains only one type of atom
5
Q
Energy of a substance and temperature of a substance at its melting point (what happens to it)
A
Energy goes into changing the phase of a substance
6
Q
Element
A
A substance made up of only 1 type of atom
7
Q
Atom
A
Smallest part of an element to exist
8
Q
Molecule
A
A small group of atoms that are covalently bonded
9
Q
Compound
A
A pure substance made of 2 or more different elements chemically bonded
10
Q
Mixture
A
A mixture contains 2 or more substance not chemically joined together
11
Q
What symbol do these elements have
Gold
Lead
Silver
A
Gold - Au
Lead - Pb
Silver - Ag
12
Q
Iron sulphide word equation
A
Fe + S = FeS
13
Q
Classify elements
A
Elements can be classifed as metals, non-metals and metalloids
14
Q
Classify compounds (what type are they)
A
Compounds are classifed as inorganic and organic compounds
15
Q
What happens to mass in a chemical reaction
A
Mass is conserved
16
Q
Relative mass of subatomic particles
A
Protons 1
Neutrons 1
Electrons -1
17
Q
Why is mass conserved in a chemical reaction
A
No new atoms have entered or left the system so the mass is conserved
18
Q
Significance of chemical symbols used in formulae and equations
A
Useful to write a chemical formula of any compound in a short form
19
Q
How mass may appear to change in a chemical reaction
A
If a gas escapes the total mass will look as if it has decreased
20
Q
Phosphorus
A
P
21
Q
John Dalton’s model of atom
A
Billiard ball model
Atoms were of a ball like structure
22
Q
John Jacob Berzelius model of atom
A
Intoduced simple alphabet characters to symbolize each element
23
Q
Joseph John Thomson model of atom
Plum pudding model
A
A sphere with protons and electrons mixed together
24
Q
Ernest Rutherford model of atom
Nuclear model
A
An outer shell with protons and the nucleus at the centre and electrons surrounding the nucleus
25
Niels Bohr atom model
Planetary model
Electrons spin around nucleus in orbits
26
Difference between plum pudding model and nuclear model
Nuclear model has a positively charged nucleus
Plum pudding - electrons and protons mixed together
27
How evidence from scattering experiments changed the model of atom
Results from alpha scattering led the plum pudding model replaced by the nuclear model
28
Describe atoms using the atomic model
Atoms contain electrons protons and neutrons
Electrons orbit the nucleus in energy levels
Protons and neutrons found in nucleus
29
Why model of atom changed overtime
Scientists changed the model so it could explain new evidence
30
How to describe familiar chemical equations
Reactants -----> products
31
Ion
Atom or a group of atoms with positive or negative charge as a result of having lost or gained one or more electrons
32
Why ions have a charge
The number of electrons doesn't equal the number of protons in the atom
33
Isotopes
Forms of an element with the same number of protons but different number of neutrons
34
How to describe isotopes using atomic model
Atoms with different numbers of protons and nuetrons
35
What are the patterns in periodic table
Atomic radius
Mass number
Reactivity
36
Why can we be sure that there are no missing elements in first 10 elements of periodic table
Any atom with 6 protons is carbon, it cannot be anything else
All the other elements have a number of protons which no other element has the same number
37
How to work out atomic number of an element
Number of protons = atomic number
Number of electrons = atomic number
38
How to work out number of neutrons
Mass number - atomic number
39
How to work out mass number
Number of neutrons + number of protons
40
Size of an atom in standard form
-10
1 x 10 m
41
Why chlorine does not have a whole mass number
Due to involvment of isotopes
42
Why elements in same group react in a similar way
They have similar number of valence electrons
43
What happens to electrons the further down the energy levels they go
Their energy increases the longer the line
44
State relative mass of a nucleus
-15
10 m
45
State maximum number of electrons in the first 3 energy levels
1st shell - 2
2nd shell - 8
3rd shell - 18
46
How we can make predictions for how an element will react when given information on another element in the group
Elements in same group have similar chemical properties
There's usually a pattern in their physical properties
47
List the significant models for ordering the elements
Periodic table
Relative atomic masses
48
How the elements are ordered in the perioic table in groups and periods
In order of increasing atomic number
49
Why ordering of elements has changed over time
Henry Moseley rearranged the elements to their atomic numbers
This helped explain disparities in earlier versions that used atomic mass
50
Why the periodic table was a breakthrough in how to order the elements
Mendeleev found out not all elements have been discovered yet
He left gaps on the table to place elements scientists didn't know yet
51
Define groups and periods in the perioidc table
Groups - columns in the periodic table
Periods - rows
52
How electronic structure is linked to periodic table
Number of electrons in the outermost shell of an element is represented in the periodic table as group number that element is in
53
Why noble gases are unreactive
The atoms of noble gases have complete outer shells so they don't lose, gain or share electrons making them unreactive
54
Boiling point and melting point trend in melting points
Boiling point - increases
Melting point - decreases
55
How electronic structure of metals and non-metals are different
Atoms of metal elements give away electrons in their reactions to form positive ions
Electrons in non-metals are localized in covalent bonds
56
How electronic structure of metals and non-metals affects their reactivity
Atoms of elements give away electrons in their reactions
Atoms of non-metals gain electrons in some of their reactions
57
In terms of electronic structure how elements in periodic table are arranged
By increasing atomic number
58
How to use periodic table to make predictions about the electronuc structure and reaction of elements
The electronic structure of an atom can be predicted from its atomic number
59
First 3 elements in group 1
Hydrogen
Lithium
Sodium
60
Features of group 1 metals
Soft
Silver metals
Low density
Low melting point
Highly reactive
61
What happens when group 1 metals react with non-metals
Group 1 metals form ions with +1 charge
62
Why the elements in group 1 react similarly
The elements in group 1 all have 1 electron in their outer electron shell
This means they share similar properties and behave similarly in chemical reactions
63
Why first 3 elements group 1 float on water
Lithium sodium potassium are less dense than water
64
How hydrogen and metal hydroxides are made when group 1 metals react
Hydrogen gas is given off and the metal hydroxide is produced
65
Name the first 4 elements group 7
Fluorine
Chlorine
Bromine
Iodine
66
How to recognise a halogen displacement reaction
The reaction mixture turns darker and iodine solution forms
67
Why elements group 7 react similarly
They have the same number of electrons in their outer shell
68
How group 1 metals are stored and safety precautions used when dealing with them
Should be stored in mineral oil or kerosene
Do not expose to air or water
Avoid contact with skin and eyes
69
How Group 7 non-metals form ions with a −1 charge when they react with metals
When group 7 element takes part in a reaction its atoms each gain 1 electron forming a negatively charged ion
70
Main properties of halogens
7 valence electrons
Halogens have 1 electron missing as they form negative ions
Highly reactive
71
How to compare the reactivity of the Group elements
As you go down group 7 reactivity of halogen decreases
Electronic structure - the atomic mass of the halogen increases
72
The trend in reactivity group 1
The reactivity increases as you go down the group
Electronic structure - the atoms get larger
73
Use electronic structure to explain trends in physical and chemical properties of group 1
When an element in group 1 takes part in a reaction its atoms loses their outer electron and form positively charged ions
74
Use electronic structure to explain trends in physical and chemical properties of group 7
The group 7 elements gain one more electron so they have a stable electronic structure
75
Use the nuclear model to explain how the outer electrons experience different levels of attraction
Attraction between the nucleus and the outer electrons increases across a group because the proton number increases
76
Why mercury is not a typical transition element
Neither the atom or its cations possess an incomplete d-subshell
77
Chemical properties of transition metals and their compounds
Good conductors of heat and electricity
High melting points
Usually hard and tough
High density
78
Justify the use of a transition metal
Used in construction materials
tools, vehicles
79
Compare group 1 metals and transition
Transition metals are much stronger, denser and harder than group 1
80
Why group 1 metals have different properties to transition metals
As 3d electrons delocalise the number of electrons involved in metallic bonding increases
81
Trend in group 2 reactivity
Increases
Outer electons easier to remove
82
Trend in group 6 reactivity
Decrease
Electronegativity decreases
83
State the particles involved in ionic and covalent bonding
Covalent - a pair of electrons shared between 2 atoms
Ionic - a cation and an anion
84
How a group 1 metal atom becomes a positive ion
When metals in group 1 lose 1 electron they become ions with a +1 charge
85
Examples of how group 1 metal becomes positive ion
Lithium has 1 electron in its outer shell which it needs to lose and when losing this electron lithium becomes an ion
86
Describe with an example how a group 7 non-metal becomes a negative ion
Fluorine will gain one electron to become a negative fluroide ion
-
F
87
How a group 7 non-metal becomes a negative ion
Non-metals of Group 7 need to gain 1 electrons
