Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Science year 8 > Chemistry > Flashcards

Chemistry Flashcards

Be the true sigma and master all the elements needed for term 3 chemistry (91 cards)

Start Studying
1
Q

Elements (list examples)

A

Substances made up of one type of atom
Eg. Phosphorus and Sulfur and various metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Compound

A

Made up of more than one type of atom but only one type of molecule
The properties of compounds are different from their atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Molecules

A

Made up of one or more atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is everything made up of?

A

Atoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are compounds formed?

A

When two or more elements combine (elements like the ones on the periodic table)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are elements made of?

A

Atoms or Molecules
Eg. Helium is made up of just one atom so it isn’t made of Molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How can the difference be told between if an element stands as made up of a single type of atom or as a molecule in written form?

A

If a number 2 or above
hasn’t been put next to it’s chemical symbol then that element is made up of one type of atom. If a number 2 or above is present then that element is made up of a molecule/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens when elements and compounds combine?

A

They form mixtures in the form of solid, liquid or gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

An example of a compound

A

C (Carbon) + O2 ( 2 Oxygen) = (meant to be an arrow when drawn but no arrow is on the keyboard) CO2 (Carbon dioxide)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What 3 sub-atomic particles is an atom made up of and where are they located?

A

Protons, Neutrons and Electrons and they are located in the Nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Atomic number

A

Goes on the top and is the number of Protons in an atom and helps determine the amount of electrons as they are the same

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Atomic mass

A

The sum of Protons and Neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Different groups in the periodic table

A

Alkali metals, Alkali Earth Metals, Noble Gases, Halogens, Transition metals, Basic metals, Metalloids, Non-Metals, Rare-Earth Metals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Alkali characteristics/features/properties

A

Excellent conductors of heat and electricity, high (silver) lustre (light), high ductility (flexibility), and malleability (ability to be molded), tarnish readily in the air, can be cut with a knife, most reactive metal elements and have only 1 electron in their valence shells and are solid at room temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Alkali Earth Metals characteristics/features/properties

A

Highly metallic and are good conductors of electricity and have a shiny silver-white lustre, they have 2 electrons in their valence shells, they are solids at room temprature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Halogens characteristics/features/properties

A

Low solubility and the most reactive non-metals as they are just one electron away from a full valence shell making them unstable, they have 7 electrons in their valence shell, are gas at room temprature and are toxic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Noble gases characteristics/features/properties

A

Colorless, odorless, tasteless, and appear as a gas at room temperature and are the least reactive elements as they have a perfect full valence shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Metalloids

A

Are elements which can act as either a metal or non-metal under certain conditions meaning under correct conditions they can be good conductors of heat and electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Transition metals

A

Are elements which are good conductors of heat and electricity, are
malleable and are generally solids at room temperature, and they are unique as they vary amount of electrons in the valence shell, Copper and Iron are two metals that are essential to our modern technology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Non-Metals

A

Are elements which are not good conductors of heat and electricity, not malleable and most are gases at room temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Rare-Earth Metals characteristics/features/properties

A

Last group on the periodic table, consist of rare metals and radioactive metals that are natural on Earth, they are found as metals at room temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does it mean to ‘tarnish readily in the air’?

A

To become dull or discoloured in the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What 3 categories can elements on the periodic table labelled as?

A

Metals, Non-Metals and Metalloids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why do the Electrons orbit around the Neutrons and Protons?

A

This is as the Electrons are attracted to the Protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Who made the atom theory?
Neil Bohr and he named them Bohr diagrams
26
What is the equation to find the amount of electrons in each shell?
2 times the amount of shells squared Eg. For 3 shells = 2 x 3^2 = 18
27
How do the rows work in the periodic table?
Each row from the bottom increases with the amount of electrons in the valence shell
28
How is shell notation written?
By writing down the amount of electrons in each shell Eg. For aliminium it would be 2,8,3
29
Explain the 2,8,8,2 rule
It states that for the first 20 (but mainly just for 19 and 20 but it can work the other elements but it would be 2,8,8) elements, since electrons will always fill the lowest energy level first once the shell starts to get larger it is actually easier for it to pass the electrons onto the next shell as the 4th shell will have less energy so it will be easier for the electrons
30
Why are atoms considered 'selfish'?
This is as they would do anything to get to 0 or 8 electrons in their valence shell. Sodium and Fluorine for example: Sodium has 1 electron in its valence shell so it wants to get to 0 and Fluorine has 7 electrons and it wants to get to 8 electrons. So Sodium can give one electron to Fluorine to make both of them 'happy'
31
What are 'Ions' and how are they formed?
Ions are charged atoms and they form when atoms give or take electrons and become charged
32
What are 'Cations' and how are they formed?
They are positively charged atoms and they form when atoms lose an electron and become positively charged
33
What are 'Anions' and how are they formed?
They are negatively charged atoms and form when an atom gains an electron and becomes negatively charged atom
34
How can Sodium (1 valence electron) and Oxygen (6 valence electron) balance things out?
2 sodium atoms will be needed for 1 oxygen atoms. This means 2 Sodium Cations form and 1 Oxygen Anion forms
35
How can new Ions be renamed?
In the Sodium and Oxygen example for example, Na^+O^-2 = Take the top number of the Oxygen and place it on the bottom of the opposite Ion (Sodium). Then take the number at the top of Sodium and place it on the opposite Ion (Oxygen) Na2O (The two is on the bottom of 'a' and the + symbol is not needed to show as it just represents 1 which does not need to be shown
36
How can the number of Neutrons be determined?
Number of Neutrons = Relative (rounded) atomic mass - Atomic number Eg. Lithium = 6.941 - 3 = 3.941 *DO NOT ROUND THE FINAL NUMBER*
37
What is an 'Isotope'?
Atoms which have the same number of Electrons and Protons but a different amount of Neutrons
38
What is the Isotope notation?
Atomic mass on the top and the Atomic number on the bottom
39
What are acids known as and where are they found?
They are known as Proton Donors (H^+) and they are found in foods, cleaning products and digestion fluids
40
What are Bases known as, what is the alternative name for it and where are they found?
Bases are known as Proton Acceptors (H+) and the alternative name for them is Alkaline and they are found in foods, cleaning products and soap
41
What is the PH scale and define how it works
The PH scale is a scale that allows to identify if substances are bases or acids A substance is Acidic when it has a pH value below 7.0 A substance is Basic (or Alkaline) when it has a pH value above 7.0 A substance is Neutral when it has a pH value of exactly 7.0
42
How does the PH scale function (what does it measure)?
It measures the amount of free Hydrogen Ions in a solution. If the amount of free Hydrogen Ions is low in a solution the PH is high (base) and if high then Ph is low (acid). Everytime you take a step along the PH scale it decreases by 10x less and if it goes backwards then it increases by 10x
43
What are the 3 ways to measure PH value?
Indicator Litmus Paper Chemical Reactions
44
What happens when objects are placed in both acids and bases?
The object in the bases gets breaken up/more damaged than the acids however both get release heavy amounts of smoke. One example of this is the coca-cola experiment where aliminium cans were placed in both acids and bases. This does not mean bases are stronger however as a rule goes that the strongest base is the weakest acid and the strongest acid is the weakest base
45
What is an universal indicator?
Chemical which changes colour when mixed with an acid or a base
46
What colours indicate what in terms of acids and bases?
If red, orange, yellow or a swampy-green - strongly acidic If light green, a little bit darker than light green and a little bit darker than that light green - weakly acidic Normal green - Neutral Cyan, dark blue and navy blue - weakly alkaline Dark grey, grey, maroon and dark brown - strongly alkaline
47
What is 'Limtus Paper'?
A special type of paper which has been treated with chemicals which change colour when mixed with an acid or a base
48
What are the 3 types of 'Limtus Paper'?
Universal Litmus Paper Red Litmus Paper – Turns Blue when mixed with a Base Blue Litmus Paper – Turns Red when mixed with an Acid
49
How does chemical reactions work to measure pH and give an example
For this to work the chemical reaction must be known first to know what to look for (eg. bubbles, colour change, change of heat etc...) Example : magnesium ribbon where a ribbon is mixed with base and acid and acid is way more bubblier. The mixing of two materials is the chemical reaction part of it all
50
What is Neutralisation?
When acids and bases mix and a chemical reactions occurs. This leads to Acid + Bases = Water + Chemical Salt
51
What are the 3 primary types of bonding?
Ionic Covelent Metallic
52
What is ionic bonding and give the 4 properties
When an caution and an anion interact. They both attract and bond together. For example for Sodium Fluoride to form the Sodium has to give one electron to the Fluorine making the Sodium the caution and Fluorine the anion. They both attract and form Sodium Fluoride. Some properties include : Water Soluble, High Melting Point, Brittle (hard but liable to break), Electrically Conductive (when full of water)
53
Covalent bonding and the 3 properties of it
Covalent bonding occurs when two elements share the same electron This is common along groups 3-7 An example of this is when two Hydrogen elements share and become H2 (with the two on the bottom) No ions are formed The properties are: Low Melting Point No electrical conductivity Not Water Soluble
54
Metallic bonding and the 4 properties
When two or more metal compound join together to form a 'sea of electrons' Metal elements want to lose their electrons to have 0 in the valence shell The 4 properties: Electrically Conductive Not Water Soluble Very Strong Malleable
55
Metallic Lattice
If they can't find another element to take their electrons then they will interact with other metal elements. They lose all of their valence electrons which form a sea and the electrons move in between the metal cations. It is held together by the attraction between the metal elements and the negatively charged electrons making it very strong
56
What does an ionic bonding look like in a diagram?
Imagine a six on a normal dice and the bottom left, middle right and the top left circles are one element and the rest are other elements
57
What does a covalent bonding look like in a diagram?
A venn diagram but the outer two circles have the elements on them and the middle circle has the amount of electrons (the atomic number)
58
What does a metallic bonding look like in a diagram?
Imagine a six on a normal dice and there is electrons floating between the circles
59
How are chemical reactions formed and what are the four components and give an example of the notation
It occurs when two or more substances are converted into a new set of substances It's four components are: the reactants, the products, the direction of the reactants, the physical state of each component Example of notation: Reactant + Reactant = Product + Product (= meant to be arrow)
60
3 steps of writing chemical notation
1. Identify the products and the reactants 2. Place an arrow from the reactants to the products 3. Place the states of each of the chemicals below in a shortened form Solid = s Liquid = l Gas = g Aqueous = aq
61
What is an aqueous?
A system/substance that involves water
62
Elemental Molecules
Are elements made up of more than one type of atom Written with a two on the bottom and form through covelent bonding
63
First law of Thermodynamics
Matter is nor created nor destroyed (like atoms)
64
What type of charge is cation and anions?
Cation - Positve Anion - Negative
65
Precipitation reactions
Occur when cations and anions in aqueous solution combine to form an insoluble ionic (made from ions) solid called a a precipitate
66
Combustion reactions and one example
A reaction where a substance reacts with oxygen gas, releasing energy in the form of light and heat and is basically a fire which people use to warm things up and combustion reactions go on inside of the fire. If oxygen, fuel or heat is removed then the fire goes out eg. a candle burning, etc......
67
Fossil fuels and one example
A non-renewable energy source eg. coal
68
What are fossil fuels made of?
Hydrocarbons which are made of hydrogen and carbon atoms
69
What happens to fossil fuels when going through combustion?
The carbon compound reacts with oxygen in the presence of a heat source to form Carbon Dioxide and water CH4 + O2 = CO2 + H2O (= is meant to be arrow)
70
Why is carbon in every fossil fuel combustion reaction?
This is as all fossil fuels are made of carbon
71
Solubility rules
Some compounds containing certain ions can not precipitate as they will dissolve in water Some compounds containing certain ions are soluble, except when containing certain other ions, making them not form a precipitate Some compounds are only slightly soluble
72
Can soluble compounds/ions form precipitates?
No, only insoluble compounds can form precipitates
73
Physical change
Involve a change in state Nothing new is formed Are easily reversible
74
Chemical change
A change in temperature Seeing bubbles being produced – which tell you a gas has been formed. A permanent colour change. A new solid is formed (called a precipitate) Energy (for example heat or light) is produced or absorbed.
75
What do the numbers below the chemical symbol show?
How many atoms are in that element. If no number is present then it means that element is made up of one type of atom.
76
What occurs in chemical reactions?
Atoms are not created nor destroyed, they simply rearrange The atoms involved rearrange to create new substances
77
Reaction rate meaning
A measure of how quickly a chemical reaction occurs
78
Examples of reaction rates
Chemical reactions cause explosions to release quickly Chemical reactions take a slow time to set concrete
79
Factors that affect reaction rates
Surface area Concentration of a reactant Pressure Temperature Presence/absence of a catalyst
80
What is surface area?
The exposed area of a solid substance
81
Example of how surface area affects reaction rates?
In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form smaller lumps (lumps as in group of smt) however, the number of collisions per second between magnesium and hydrogen is higher, and the rate of reaction is faster. NOTE -This is as when grouped the middle atoms can not be touched but when split up into different sections, all atoms can be reacted with, increasing the reaction rate
82
Concentration
Note - Concentration means when there is more of smt When there is more atoms of a Reactant, there is more collision increasing the reaction rate
83
Goofy IRL example of conecentration
If you put 30 blindfolded and mute men in a room and tell them a bear is there they will all collide. However, if there is 100 men then they collide faster
84
Pressure
Putting pressure on gas molecules allows for less volume and more collision of the gas molecule increasing the reaction rate. For the same, if the volume is increased the pressure is decreased and collision is less frequent meaning the reaction rate is slower
85
Temprature
If the temperature is increased: the reactant particles move more quickly they have more kinetic energy the particles collide successfully more often the rate of reaction increases
86
Catalysts
Substance that change the rate of chemical but remain unchanged themselves and not all catalysts are suitable for certain reactions
87
3 types of Catalysts
Catalysts in industry Catalysts in every day life Catalysts in living things
88
What is electron configuration?
The amount of electrons in each shell Eg. C = 2,4
89
How can the difference between Cations and Anions in a chemical equation be shown?
Na^+Ca^+2 The '+' sign shows a Cation and the '+2' shows that two electrons have been lost If there was a '-' sign it would show an Anion and if it were to say '-2' then it shows that two electrons have been gained
90
Why is the atom mass a decimal a lot of the time?
This is as the atomic mass is the average of all of the Isotope atoms in the element. For example, Lithium has an atomic mass of 6.941 as it is the average of all of the Isotopes
91

Science year 8 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions