Atomic theory 1 Flashcards
1
Q
Define Element
A
A substance that cannot be broken down into simpler substances by chemical means.
2
Q
How are elements arranged horizontally?
A
In periods
3
Q
How are elements arranged vertically?
A
In groups
4
Q
What does the number of electrons in the outer shell give rise to and what does it mean?
A
Valency - which means the number of chemical bonds an element can make.
5
Q
What is the name of group 1
A
Alkali metals (1 electron in outer shell, valency =1)
6
Q
What is the name of group 2
A
Alkaline earth metals (2 electrons in outer shell, valency = 2)
7
Q
What is the name of group 7
A
Halogens( 7 electrons in outer shell, valency = 1)
8
Q
What is the name of group 0?
A
Noble gases ( 8 electrons in outer shell, valency = 0\0
9
Q
Protons
A
Positively charged
10
Q
Neutrons
A
Neutral
11
Q
Electrons
A
Negatively charged
12
Q
Where are protons and neutrons found?
A
In the nucleus of the atom
13
Q
Where are electrons in orbitals (sub-levels) found?
A
Around the nucleus
14
Q
Do ions have a charge?
A
Yes
15
Q
Do atoms and molecules have a charge?
A
No they are neutral
16
Q
Are the words atoms and ions interchangeable?
A
No as atoms and ions are completely different
17
Q
What is the whole number above the symbol for the element called?
A
The atomic number (Z)
18
Q
What is the decimal number below each element called?
A
The relative atomic mass number (Ar)
19
Q
What does the atomic number tell us?
A
The number of protons an atom of the element will have.
20
Q
What does the relative atomic mass give?
A
An average mass of all known isotopes of that element.
21
Q
Define metal
A
Any element that loses electrons to form a positive ion (cation).
22
Q
Define atomic number
A
The number of protons present in the nucleus of an atom.
23
Q
Define mass number
A
The mass number is the number of protons plus neutrons in the nucleus of an atom.
24
Q
Define isotopes
A
Isotopes are atoms of the same element that have the same atomic number but different mass numbers due to the different numbers of neutrons present in the nucleus.
25
Define relative atomic mass number
The average mass of an atom of an element compared to 1/12 the mass of the carbon - 12 isotope, taking relative abundances of the naturally occurring isotopes into account.
26
What is valency linked to?
'Octet rule'
27
Valency of group 1
1
28
Valency of group 2
2
29
Valency of group 3
3
30
Valency of group 4
4
31
Valency of group 5
3
32
Valency of group 6
2
33
Valency of group 7
1
34
Valency of group 8
0
35
Alkali metals
- Extremely reactive
- Soft metals
- Low densities
- Shiny when freshly cut but tarnish rapidly due to reaction with air
36
Alkali metal + oxygen gas -->
Metal oxide
37
Alkali metal + water -->
Metal hydroxide + hydrogen gas
38
Alkaline earth metals
- Very reactive but less reactive than the alkali metals
| - Magnesium reacts slowly with water
39
Halogens
- Very reactive non-metals
| - Low melting and boiling points
40
Noble gases 3
- Gaseous at r.t
- B.P increases down group
- Least reactive of all elements (as have 8 electrons in outer shell - except He which has 2 electrons in its only shell)
41
What can particles be?
Atoms, molecules or ions.
42
Where is the mass of an atom concentrated?
In a small central nucleus consisting of protons and neutrons.
43
What is around the nucleus?
Electrons
44
Why can the mass of an electron often be ignored?
As its so small
45
In an atom what does the number of electrons always equal to?
The number of protons in the nucleus
46
What does the total negative charge equal?
The total positive charge
47
Atoms are
Neutral
48
On going from left to right across the periodic table the elements get ….
Less metallic in nature and more gaseous
49
What are H2,N2,O2,F2 & C2 at r.t?
Gaseous % diatomic
50
Can H2,N2,O2,F2 & C2 be found on their own in nature?
No
51
What is the only metal that is liquid at r.t?
Hg
52
What is Br2 (non-metal) at r.t?
Liquid, exists diatomically
53
What is I2 (non-metal) at r.t?
Solid, exists diatomically
54
What are C, Si, P & S (non-metals) at r.t?
Solids, exist mono-atomically
55
What are all noble gases as r.t?
Gaseous
56
How do noble gases exist?
Mono-atomically
57
How many isotopes does carbon have?
3
58
How many isotopes does hydrogen have?
3
59
Why is the relative atomic mass number rarely a whole number?
As it is the average of all known isotopes of an element.
60
Define relative molecular mass number (Ar)
The average mass of a molecule of a compound compared to 1/12 the mass of the carbon - 12 isotope, taking relative abundances of the naturally occurring isotopes into account.
61
How do you get the Mr?
By adding together the relative atomic masses present in a molecule
62
What do atoms do to form ions?
They gain or lose electrons
63
What happens if an atom loses an electron?
A positive ion will be formed
64
What happens if an atom gains an electron?
A negative ion will be formed
65
What is another name for positive ions?
Cations
66
What is another name for negative ions?
Anions
67
Do metal atoms tend to gain or lose electrons?
Lose electrons (to form cations)
68
Do non-metal atoms tend to gain or lose electrons?
Gain electrons (to form anions)
69
Naturally occurring chlorine consists of 75.5% of (35)Cl and 24.5% of (37) Cl. Calculate the relative atomic mass (Ar) of chlorine. (L.C)
- 75.5 x 35 = 2642.5
- 24.5 x 37 = 906.5
100 atoms = 3549
1 atom = 35.49 (Ar)
70
*Metal + oxygen =
Metal oxide
71
*(usually metals from group 1 or 2)Metal + water =
Metal hydroxide + hydrogen gas
72
A dipositive ion, M2+, has 25 electrons and 32 neutrons. What is (i) the atomic number, (ii) the mass number, of M (L.C)
i) 27
| ii) 59
73
What are isotopes? (L.C)
Atoms with the same atomic number (Z) but different mass numbers (A)
74
How many (i) electrons, (ii) neutrons, has the aluminium ion Al3+ (L.C)
i) 10
| ii) 14
75
Explain why relative atomic masses are rarely whole numbers. (L.C)
As it is the average of mass numbers of the isotopes of an element
76
Define (i) mass number, (ii) relative atomic mass (L.C)
(i) number of nucleons (protons and neutrons) in the atoms of an isotope
(ii) Average mass of atoms of element relative to 1/12 of mass of carbon-12 atom
77
A sample of the element gallium is composed of 60.1% gallium-69 and 39.9% gallium-71. Calculate the relative atomic mass of gallium from this information. (L.C)
69 x 60.1 = 4146.9
71 x 39.9 = 2832.9
100 atoms = 6979.8
Ar = 69.798 (69.8)
78
Define relative atomic mass (L.C)
Average mass of atoms of element relative to 1/12 mass of carbon-12 atom
79
Define relative atomic mass (L.C)
Average mass of atoms of element relative to 1/12 mass of carbon-12 atom
80
Define (a) atomic number, (b) relative atomic mass (L.C)
a) Number of protons in the nucleus of an atom of the element
b) Average mass of atoms of element relative to 1/12 mass of carbon-12 atom
81
What are isotopes? (L.C)
Atoms with the same atomic number (Z) but different mass numbers (A)
82
What are isotopes? (L.C)
Atoms with the same atomic number (Z) but different mass numbers (A)
83
What is the principle of the mass spectrometer? (L.C)
Positive ions separated based on relative mass when moving in a magnetic field
84
Calculate, to two decimal places, the relative atomic mass of a sample of neon shown by mass spectrometer to be composed of 90.5% of neon-20 and 9.5% of neon-22. (L.C)
90.5 x 20 = 1810
9.5 x 22 = 209
100 atoms = 2019
Ar = 20.19
85
What are isotopes? (L.C)
Atoms with the same atomic number (Z) but different mass numbers (A)
86
Define relative atomic mass, Ar (L.C)
Average mass of atoms of element relative to 1/12 mass of carbon-12 atom
87
What is the principle on which the mass spectrometer is based?
Positive ions separated based on relative mass(es) when moving in a magnetic field
88
Calculate the relative atomic mass of a sample of lithium, given that a mass spectrometer shows it consists of 7.4% (6)Li and 92.6% (7)Li (L.C)
7.4 x 6 + 92.6 x 7 = 692.6
100 atoms = 692.6
1 atom = 6.926
89
Is Na+ an atom, molecule, simple ion or a complex ion?
Simple ion
90
Is K an atom, molecule, simple ion or a complex ion?
Atom
91
Is SO2+ an atom, molecule, simple ion or a complex ion?
Complex ion
92
Is I2 an atom, molecule, simple ion or a complex ion?
Molecule
93
Is F- an atom, molecule, simple ion or a complex ion?
Simple ion
94
Is Fe an atom, molecule, simple ion or a complex ion?
Atom
95
Is KMn04 an atom, molecule, simple ion or a complex ion?
Molecule
96
Is 02- an atom, molecule, simple ion or a complex ion?
Complex ion
97
What is the atomic number of sulfur?
16
98
What is the atomic number of calcium?
20
99
What is the atomic number of iron?
26
100
What is the atomic number of bromine?
35
101
What is the relative atomic mass number of sulfur?
32
102
What is the relative atomic mass number of calcium?
40
103
What is the relative atomic mass number of iron?
56
104
What is the relative atomic mass number of iodine?
154
105
How many (i) protons, (ii) neutrons and (iii) electrons in (35) Cl?
(i) 17p
(ii) 18n
(iii) 18e
106
Identify the element that has 60.4% of atoms with a mass of 69 and a remainder with a mass of 71.
Gallium
107
What is the relative atomic mass of magnesium which normally consists of 78.6% magnesium-24, 10.1% magnesium-25 and 11.3% magnesium-26?
24.31 (check this)
108
Identify an element that is a non-metal and is liquid at room temperature.
Br
109
Identify an element that is a divalent metal.
Anyone from group 2 (Be, Mg, Ca...)
110
Identify an element that exists in both diatomic and triatomic states.
Oxygen
111
Identify an element that has an atomic number of 26
Fe
112
- Florine and chlorine
Halogens
| yellow-green gases
113
Bromine
Halogen
| a red liquid
114
Iodine
Halogen
| a dark solid at room temperature
