1
Q
In chemistry, what is all matter composed of?
A
Atoms.
2
Q
What is the smallest unit of an element that retains its properties?
A
The atom.
3
Q
How is each element represented on the Periodic Table?
A
By a unique chemical symbol.
4
Q
In atomic structure, what is found in the nucleus?
A
Protons and neutrons.
5
Q
In atomic structure, where are electrons located?
A
In energy levels/orbitals around the nucleus.
6
Q
What does an element’s atomic number tell you?
A
Number of protons.
7
Q
How do you find the number of neutrons in an atom?
A
Neutrons = mass number − atomic number.
8
Q
In a neutral atom, how do electrons compare to protons?
A
Electrons = protons.
9
Q
What did Mendeleev do for the Periodic Table?
A
Arranged elements by atomic mass and properties, leaving gaps for undiscovered elements.
10
Q
Why was Mendeleev’s Periodic Table important?
A
It predicted properties of undiscovered elements.
11
Q
For the first 20 elements, what is the electron arrangement pattern?
A
2, 8, 8, 2.
12
Q
When drawing a Bohr model, where do protons and neutrons go?
A
In the nucleus.
13
Q
When drawing Bohr models, where do electrons go?
A
In shells/energy levels around the nucleus.
14
Q
How do you use the Periodic Table to find proton number?
A
Proton number equals atomic number on the table.
15
Q
How do you use the Periodic Table to find electron number in a neutral atom?
A
Electron number equals atomic number.
16
Q
How do you use the Periodic Table to find neutron number?
A
Subtract atomic number from mass number.
17
Q
Which group is called alkali metals?
A
Group 1.
18
Q
Which group is called alkaline earth metals?
A
Group 2.
19
Q
Which block is called transition metals?
A
The central d-block (Groups 3–12).
20
Q
Which group is called halogens?
A
Group 17.
21
Q
Which group is called noble gases?
A
Group 18.
22
Q
On the Periodic Table, how does metal reactivity change down Group 1?
A
Reactivity increases down Group 1.
23
Q
On the Periodic Table, how does non-metal reactivity change down Group 17?
A
Reactivity generally decreases down Group 17.
24
Q
Why are Group 1 metals very reactive?
A
They have one valence electron that is easily lost.
25
Why are Group 17 halogens very reactive?
They need one electron to complete the valence shell.
26
In ionic bonding, which type of element loses electrons?
Metals lose electrons to form cations.
27
In ionic bonding, which type of element gains electrons?
Non-metals gain electrons to form anions.
28
What is the force holding ionic compounds together?
Electrostatic attraction between oppositely charged ions.
29
What does an ionic compound form in the solid state?
A giant ionic lattice.
30
How do you draw ionic bonding for NaCl?
Show Na losing 1e⁻ → Na⁺ and Cl gaining 1e⁻ → Cl⁻ with brackets and charges.
31
What is meant by “rearranging atoms” in chemical reactions?
Atoms are rearranged into new compounds; no new atoms are created.
32
How do we know mass is conserved in reactions?
Total mass of reactants equals total mass of products.
33
What does a balanced chemical equation show?
Atoms of each element are conserved.
34
What is the general product of acid + metal?
Salt + hydrogen gas.
35
What is the general product of acid + metal carbonate?
Salt + CO₂ + water.
36
When naming ionic compounds, which ion is named first?
The cation (positive ion).
37
Give an example of writing an ionic formula from ions Na⁺ and SO₄²⁻.
Na₂SO₄.
38
In covalent bonding, which elements bond this way?
Non-metals with non-metals.
39
What happens to electrons in covalent bonding?
Electrons are shared between atoms.
40
How do you draw a simple cross-and-dot diagram for H₂?
Two H atoms share one pair of electrons.
41
How do you draw a cross-and-dot diagram for H₂O?
O shares two pairs, one with each H.
42
How do you name simple covalent compounds?
Use prefixes (mono, di, tri) and end in “-ide”.
43
What does the Law of Conservation of Mass state?
Matter is not created or destroyed in chemical reactions.
44
In a flame test, what causes the colour?
Electrons fall from excited states and release characteristic light.
45
Why do different metal ions give different flame colours?
Different energy gaps between electron levels.
46
What does an electron energy level model show?
Electrons arranged in shells around the nucleus.
47
Give one everyday example of light absorption.
Black shirt absorbing sunlight.
48
Give one everyday example of light reflection.
Mirror reflecting light.
49
Give one everyday example of light refraction.
Straw appearing bent in water.
50
What is the Law of Reflection?
Angle of incidence to the normal equals angle of reflection.
51
In waves, what is wavelength?
Distance between two corresponding points (e.g. crest to crest).
52
In waves, what is amplitude?
Maximum displacement from rest.
53
In waves, what is frequency?
Number of waves passing a point per second.
54
In waves, what is velocity?
Speed of the wave through a medium.
55
What is the wave equation?
v = fλ.
Velocity = Frequency x Wavelength
56
How does sound transfer energy in the particle model?
Particles vibrate and pass energy to neighbouring particles.
57
Why does sound travel faster in solids than gases?
Particles are closer together in solids.
58
Name the regions of the EM spectrum from lowest frequency.
Radio, microwave, infrared, visible,UV, X-ray, gamma.
59
What EM waves are often used for mobile or Wi-Fi communication?
Microwaves.
60
What EM waves are used in remote controls and thermal imaging?
Infrared waves.
61
What EM waves cause sunburn?
Ultraviolet.
62
What EM waves are used in medical imaging of bones?
X-rays.
63
In astronomy, what is a nebula?
Nebulae are giant clouds of hydrogen gas, helium gas
64
In astronomy, what is a star?
Stars are giant balls of plasma which form through nuclear fusion
65
In astronomy, what is a solar system?
A star with orbiting planets and smaller bodies.
66
In astronomy, what is a galaxy?
A huge collection of stars, gas and dust held by gravity.
67
Why do we use light-years in space?
Space distances are enormous; light-year is a useful scale.
68
What force keeps planets, stars, and galaxies attracted?
Gravitational attraction.
69
What is a scientific theory?
A well-supported explanation based on evidence.
70
According to the Big Bang theory, how did the Universe begin?
Very hot, very dense state that expanded and cooled.
71
About how long ago did the Big Bang occur?
About 13.8–14 billion years ago.
72
What observation supports the Big Bang via galaxy motion?
Redshift shows galaxies are moving away.
73
What is the Cosmic Microwave Background (CMB)?
Faint leftover radiation from the early Universe.
74
Why are hydrogen and helium abundances evidence for the Big Bang?
Early Universe should form mostly H and He, which we observe.
75
Why can scientific theories change over time?
New evidence can modify or reject them.
76
Give one phenomenon Big Bang still can’t fully explain.
Dark matter/extra gravity in galaxies (unexplained lensing).
77
What does the Theory of Plate Tectonics state?
Earth’s lithosphere is broken into moving plates on the mantle.
78
What drives plate movement in Plate Tectonics?
Convection currents in the mantle.
79
What causes convection in the mantle?
Heat from the core causes hot material to rise and cool material to sink.
80
What evidence did Wegener use for continental drift?
Continental fit, fossil matches, rock and climate evidence.
81
What is sea floor spreading?
New crust forms at mid-ocean ridges and moves outward.
82
What evidence supports sea floor spreading?
Symmetrical magnetic stripes and younger crust at the ridge.
83
What landforms form at divergent plate boundaries?
Rift valleys and mid-ocean ridges.
84
What features form at ocean–continent convergent boundaries?
Subduction zones, volcanoes, mountain chains.
85
What happens at transform plate boundaries?
Plates slide past; earthquakes occur.
86
How can volcanoes form away from plate boundaries?
Hotspots create volcanic chains (e.g. Hawaii).
87
Name a major mountain belt formed by plate collision.
The Himalayas.
88
How are earthquakes produced along faults?
Stress builds, rocks slip suddenly, releasing energy.
89
Approximately how old is the Earth?
About 4.6 billion years.
90
How do fossils support Earth’s age?
Showing the order of life's evolution and by serving as markers to date rock layers
91
What is absolute dating of rocks/fossils?
Using radioactive decay to determine actual age.
92
What does evolution describe?
Change in populations over time.
93
What does natural selection describe?
Individuals with favourable traits survive and reproduce more.
94
Why is variation important for species survival?
Provides traits that may help in changing environments.
95
Give an example of natural selection in bacteria.
Antibiotic-resistant bacteria survive and reproduce.
96
How can mutations help natural selection?
Mutations create new alleles; some are advantageous.
97
Define heredity in biology.
Passing traits from parents to offspring.
98
In mammals, what are the male reproductive organs producing sperm?
Testes.
99
In mammals, what are the female reproductive organs producing eggs?
Ovaries.
100
What is fertilisation?
Union of sperm and egg to form a zygote.
101
What is the purpose of mitosis?
Growth and repair; makes identical cells.
102
What is the purpose of meiosis?
Makes haploid gametes for sexual reproduction.
103
How many daughter cells does meiosis produce?
Four non-identical haploid cells.
104
What is the chemical nature of DNA?
Double helix made of nucleotides (sugar, phosphate, base).
105
What bases pair in DNA?
A–T and C–G.
106
What is DNA replication?
DNA unzips and makes identical copies.
107
What is the genetic code based on?
The genetic code is based on three-nucleotide units called codons
108
In protein synthesis, what is transcription?
Making mRNA from DNA in the nucleus.
109
In protein synthesis, what is translation?
Ribosome uses mRNA to assemble amino acids.
110
What is a mutation?
A change in the DNA sequence.
111
How can a mutation change phenotype?
It can change the protein made.
112
Are most mutations harmful, neutral, or beneficial?
Mostly harmful or neutral; few are beneficial.
113
How are genes passed from parents to offspring?
In gametes at fertilisation.
114
What did Mendel’s pea experiments show?
Traits are inherited in predictable ratios.
115
In genetics, what is an allele?
A different version of the same gene.
116
Define homozygous.
Two identical alleles for a gene.(AA)
117
Define heterozygous.
Two different alleles for a gene. (Aa)
118
Define phenotype.
Physical expression of a trait.
119
Define genotype.
Genetic makeup/allele combination.
120
What is a Punnett square used for?
Predicting offspring genotype and phenotype ratios.
121
In a monohybrid cross Aa × Aa, what phenotype ratio is expected?
3 : 1 dominant to recessive.
122
What is a chromosome?
Coiled DNA containing many genes.
123
What is the importance of karyotypes?
Determine sex and detect chromosomal abnormalities.
124
What is co-dominance?
Both alleles are fully expressed in the phenotype.
125
What is sex-linked inheritance usually carried on?
X chromosome.
126
In motion, what is the difference between distance and displacement?
Distance = path length; displacement = straight-line change in position.
127
In motion, what is the difference between speed and velocity?
Speed has no direction; velocity has direction.
128
What is the formula for speed?
Speed = distance ÷ time.
129
What is the formula for velocity?
Velocity = displacement ÷ time.
130
What is the formula for acceleration?
a = (v − u) ÷ t
Acceleration = ( final velocity (v) – initial velocity (u) ) ÷ time for change (s)
131
On a distance–time graph, what does a straight line show?
Constant speed.
132
On a velocity–time graph, what does the slope show?
Acceleration.
133
On a velocity–time graph, what does the area under the line show?
Displacement.
134
State Newton’s First Law.
An object stays at rest or uniform motion unless a net force acts.
135
State Newton’s Second Law.
F = m × a
F = force in newtons
M = mass in kg
A = acceleration in m/s²
136
State Newton’s Third Law.
Every action has an equal and opposite reaction.
137
What is the difference between mass and weight?
Mass is amount of matter; weight is gravitational force (mg).
138
State the Law of Conservation of Energy.
Energy cannot be created or destroyed, only transformed.
139
What is the formula for gravitational potential energy?
GPE = mgh
M = Mass (KG)
G = Gravitational Acceleration (9.8)
H = Height
140
What is the formula for kinetic energy?
KE = ½mv²
M = Mass (KG)
V = Velocity (m/s)
141
Why are systems not 100% efficient?
Some energy is transformed to less useful forms (usually heat).
142
In energy transfers, what does “useful energy” mean?
Energy in the desired form or place.
EOI 2025
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