Chemistry Revision All Flashcards
Define the ‘periodic table’
Classification of the elements based from comparing their physical and chemical properties
What is in atomic mass?
Number of protons and neutrons combined
How do you find out the number of neutrons in an atom?
Atomic mass - atomic number (protons) = neutrons in atom
What is the row in the periodic table called (horizontal) and what can you find out about it?
Periods, number of electron shells in the number of the period
What are the columns called in the periodic table? What can you find out about it?
Groups, it is number of electrons in the outer (valence) shell
Define ‘valent electron/valence shell?
Number of electrons in the outermost shell
Define ‘element’
Pure substances, cant be broken down further by chemical/physical means, made up by only 1 type of atom
Define ‘atom’
Smallest particle of chemical element that exists (buildings blocks of all matter)
Why are atoms in groups 8 and 4 not reactive?
4 - Hard to gain or lose 4 whole electrons, so hard to bond to become stable
8 - Already full, no point in losing/gaining electrons
Define ‘Ions’
If an atom loses/gains electron to become stable, gains/loses electrons so has a charge
Define ‘Anion’
When an atom gains electrons (negative charge) as more electrons compared to protons
Define ‘Cation’
When atom loses electrons (positive charge atom) as more protons than electrons (less electrons than protons)
Define an ‘Isotope’
When single element/same element has a different number of neutrons than it’s original form on periodic table (same number of protons but different number of neutrons)
What is the rule that states electrons in a re shell are ordered (2,8,8,8…)
Octet rule
Describe the subatomic particle ‘electron’
Symbol = e
Charge = -ve
Atomic mass = 0.0055
Describe the subatomic particle ‘proton’
Symbol = p
Charge = +ve
Atomic mass = 1
Describe the subatomic particle ‘neutron’
Symbol = n
Charge = neutral/no charge
Atomic mass = 1
What is a full key for a Bohr diagram
Key
p = proton (+ve) –> nucleas
n = neutron (neutral/no charge) –> nucleas
dot = electron (-ve) –> electron shell
Predict the charge of a ‘group 1’ atom if it were to bond?
1+, as it will lose 1 electron (1 less electron than proton)
Predict the charge of a ‘group 2’ atom if it were to bond?
2+, as it will lose 2 electron (1 less electron than proton)
Predict the charge of a ‘group 3’ atom if it were to bond?
3+, as it will lose 3 electron (3 less electron than proton)
Predict the charge of a ‘group 4’ atom if it were to bond?
It needs to gain or lose 4 electrons to become stable (too much energy needed to bond)
Predict the charge of a ‘group 5’ atom if it were to bond?
3-, as it will gain 3 electron (3 more electron than proton)
Predict the charge of a ‘group 6’ atom if it were to bond?
2-, as it will gain 2 electron (2 more electron than proton)
Predict the charge of a ‘group 7’ atom if it were to bond?
1-, as it will gain 1 electron (1 more electron than proton)
Predict the charge of a ‘group 8’ atom if it were to bond?
Nothing, because it is already stable and has either 2 or 8 electrons in its outermost shell
Define ‘Inert’
Does not react
What is the chemical formula for ‘Methane’?
CH₄
What is the chemical formula for ‘Ammonia’?
NH₃
What is the chemical formula for ‘Ammonium’?
NH₄⁺
Define ‘Compound’
Pure substances chemically bonded together (only separated through chemical means, not physically)
Composed of 2/more different elements joined by chemical bonds
Define ‘Mixtures’
2 or more substances mixed together (physically)
No chemical change takes place
Separated physically
What is special about group 7?
Halogens
What is special about group 8?
Noble gases (stable)
What is special about group 1?
Alkaline Metals
What is special about group 2?
Alkaline Earth Metals
What are examples of mixtures?
Air, sea water, most rocks
What are examples of compounds?
Water
Carbon dioxide
Magnesium oxide
Sodium chloride
How can compounds be separated?
Chemical reactions, chemical means
How can mixtures be separated?
Easily, physically
What is the property of a mixture?
Each substance is easily separated from the mixture
What is the property of a compound?
The properties are different to the elements it contains
What is the composition of a mixture?
You can vary amount of each substance in a mixture
What is the composition of a compound?
It has ‘definite composition’
Cannot vary amount of each element