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Chemistry Year 8 > Untitled Deck > Flashcards

Untitled Deck Flashcards

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1
Q

What is matter?

A

Anything that has mass and takes up space.

Matter is made up of tiny particles called atoms.

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2
Q

What is an atom?

A

The smallest unit of an element that retains the chemical properties of that element.

It consists of a nucleus containing protons and neutrons, surrounded by electrons.

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3
Q

What is the composition of substances?

A

All substances are composed of atoms. In elements, all atoms are the same, whereas in compounds, different types of atoms are chemically bonded together in fixed ratios.

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4
Q

Who proposed that matter is made up of tiny, indivisible particles called ‘atomos’?

A

Democritus (5th Century BCE)

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5
Q

What did John Dalton introduce in 1803?

A

The atomic theory, stating that atoms are indivisible, different elements have different atoms, and atoms combine in fixed ratios.

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6
Q

What did J.J. Thomson discover in 1897?

A

The electron and proposed the ‘plum pudding model.’

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7
Q

What significant experiment did Ernest Rutherford conduct in 1911?

A

The gold foil experiment, leading to the discovery of the nucleus.

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8
Q

What model did Niels Bohr propose in 1913?

A

That electrons orbit the nucleus in fixed energy levels (shells).

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9
Q

What did James Chadwick discover in 1932?

A

The neutron, explaining atomic mass.

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10
Q

What is the modern quantum model of the atom?

A

Electrons exist in probability clouds called orbitals rather than fixed orbits.

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11
Q

What are the three main subatomic particles of an atom?

A
  • Protons (positively charged, found in the nucleus)
  • Neutrons (neutral charge, found in the nucleus)
  • Electrons (negatively charged, orbiting the nucleus in energy levels)
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12
Q

What is the charge of a proton?

A

+1

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13
Q

What is the charge of a neutron?

A

0

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14
Q

What is the charge of an electron?

A

-1

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15
Q

Why are atoms overall neutrally charged?

A

The number of positively charged protons equals the number of negatively charged electrons.

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16
Q

What happens when the balance of protons and electrons is disrupted?

A

The atom becomes an ion.

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17
Q

List the elements in Group 1 (Alkali Metals).

A
  • Lithium (Li)
  • Sodium (Na)
  • Potassium (K)
  • Rubidium (Rb)
  • Cesium (Cs)
  • Francium (Fr)
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18
Q

What are the properties of Alkali Metals?

A
  • Extremely reactive, especially with water
  • Soft metals that can be cut with a knife
  • Low density
  • Stored in oil to prevent reactions with air/water
  • React with water to form alkaline solutions and hydrogen gas
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19
Q

What is the reactivity trend of Alkali Metals?

A

Increases down the group; Francium is the most reactive.

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20
Q

What is an example reaction involving sodium and water?

A

2Na + 2H₂O → 2NaOH + H₂

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21
Q

List the elements in Group 2 (Alkaline Earth Metals).

A
  • Beryllium (Be)
  • Magnesium (Mg)
  • Calcium (Ca)
  • Strontium (Sr)
  • Barium (Ba)
  • Radium (Ra)
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22
Q

What are the properties of Alkaline Earth Metals?

A
  • Less reactive than alkali metals
  • Harder and denser
  • React with water but not as violently
  • Good conductors of electricity
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23
Q

What is an example reaction involving calcium and water?

A

Ca + 2H₂O → Ca(OH)₂ + H₂

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24
Q

List the elements in Group 17 (Halogens).

A
  • Fluorine (F)
  • Chlorine (Cl)
  • Bromine (Br)
  • Iodine (I)
  • Astatine (At)
  • Tennessine (Ts)
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25
What are the properties of Halogens?
* Highly reactive nonmetals * Exist as diatomic molecules * Toxic in high concentrations
26
What is the reactivity trend of Halogens?
Decreases down the group; Fluorine is the most reactive.
27
What is an example reaction involving sodium and chlorine?
2Na + Cl₂ → 2NaCl
28
List the elements in Group 18 (Noble Gases).
* Helium (He) * Neon (Ne) * Argon (Ar) * Krypton (Kr) * Xenon (Xe) * Radon (Rn) * Oganesson (Og)
29
What are the properties of Noble Gases?
* Inert due to full outer electron shells * Colorless, odorless gases * Low boiling points
30
What is the common use of Helium?
Balloons and blimps.
31
What is the common use of Neon?
Neon signs.
32
What is the common use of Argon?
Light bulbs (prevents filament burning).
33
What is the chemical formula for methane?
CH₄
34
What is the chemical formula for carbon dioxide?
CO₂
35
What is the chemical formula for carbon monoxide?
CO
36
What is the chemical formula for ammonia?
NH₃
37
What is the chemical formula for water?
H₂O
38
What is the chemical formula for glucose?
C₆H₁₂O₆
39
What is the chemical formula for sodium chloride?
NaCl
40
What makes atoms different for each element?
Each element has a unique number of protons, neutrons, and electrons.
41
How is the Periodic Table organized?
By Groups (columns) and Periods (rows).
42
What do Groups in the Periodic Table represent?
Elements with similar chemical properties.
43
What do Periods in the Periodic Table represent?
Elements with increasing atomic numbers.
44
How can elements be located on the periodic table?
By name or symbol.
45
What is the unique symbol for Hydrogen?
H.
46
What is the unique symbol for Oxygen?
O.
47
Where are metals located on the Periodic Table?
On the left side.
48
Where are non-metals located on the Periodic Table?
On the right side.
49
What are metalloids and where are they found?
Elements with properties of both metals and non-metals, found between them.
50
What are Noble Gases and their characteristics?
Inert gases with full electron shells that don’t react easily.
51
Give examples of Noble Gases.
* Helium * Neon * Argon
52
What is an element?
A pure substance made up of only one type of atom.
53
Define a molecule.
A group of two or more atoms bonded together.
54
What is a lattice?
A regular, repeating arrangement of atoms, ions, or molecules in a solid.
55
List properties of metals.
* Ductility * Malleability * Lustre * Electrical conductivity * Solid state at room temperature (except Mercury)
56
List properties of non-metals.
* Brittleness * Low conductivity * Can be solid, liquid, or gas at room temperature
57
What is a compound?
A substance made from two or more different elements that are chemically bonded together.
58
Differentiate between an element, a molecule, and a compound.
* Element: Pure substance with only one type of atom * Molecule: Two or more atoms bonded together * Compound: Two or more different elements chemically bonded
59
What is the formula for water?
H₂O.
60
What is the formula for glucose?
C₆H₁₂O₆.
61
What is the formula for methane?
CH₄.
62
What is the formula for ammonia?
NH₃.
63
What is the formula for carbon dioxide?
CO₂.
64
What is the formula for carbon monoxide?
CO.
65
What are ionic compounds?
Compounds that contain metal and non-metal elements.
66
What are covalent compounds?
Compounds formed by sharing electrons between non-metal atoms.
67
What is a physical change?
A change in form or appearance without altering chemical composition.
68
What is a chemical change?
A process that results in the formation of new substances.
69
List signs of a chemical change.
* Colour change * Gas production * Temperature change * New substance formed * Odour produced * Light or flame produced
70
What is an exothermic reaction?
A reaction that releases heat.
71
What is an endothermic reaction?
A reaction that absorbs heat.
72
What are reactants in a chemical reaction?
The starting substances.
73
What are products in a chemical reaction?
The substances produced.
74
What is a word equation in chemistry?
A description of a chemical reaction using words.
75
What is a chemical equation?
A description of the reaction with symbols and formulas.
76
What does the law of conservation of mass state?
The mass of reactants equals the mass of products.

Chemistry Year 8 (2 decks)

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