Chemistry Flashcards
Describe the structure of an atom
- atom has central nucleus
- surrounded by electrons moving around in shells/energy levels
- most of mass of atom concentrated in its nucleus (because it contains protons and neutrons)
State the mass of all the subatomic particles of an atom
Proton: 1
Neutron: 1
Electron: 1/1840
State the charges of all subatomic particles in a nucleus
Protons: +1
Neutrons: 0
Electrons: -1
What is the mass number?
total number of protons and neutrons in a nucleus
What is the atomic number?
the number of protons in the nucleus of an atom
How is electronic configuration written?
numbers with commas between:
e.g 2,8,8,1 (K - potassium)
What are isotopes?
- atoms of an element with same number of protons but different number of neutrons
- so have different mass numbers
What’s Ar
Relative atomic mass
- relative mass of its atoms compared to the mass of a particular carbon atom (carbon-12).
What are the horizontal rows on the period table called?
Periods
What are the vertical columns called on a periodic table?
Groups
How are elements arranged in the periodic table?
increasing atomic number
Group 1 elements are?
Alkali elements
Group 2 elements are called?
Alkaline earth metals
Common non-metals are found where?
Group 6
Group 7 elements are called?
Halogens
Group 8 elements are called?
Noble gases
Describe how the relationship between the position of an element on the periodic table and it’s electron configuration
- it’s group indicates how many electrons are in its outer shell
e. g. group 1 elements have 1 electron on their outer shell
-it’s period indicates how many energy levels an atom has, e.g elements in period 2 have 2 shells
Elements in the same group have what?
similar chemical properties
Trend of reactivity in metal groups (e.g. alkali metals) and in non-metal groups (e.g. halogens)
Metal groups - increases as you go down
Non-metal- decreases as you go down
What happens in a chemical reaction?
- new substances formed by rearrangement of atoms & their electrons (Think about your mechanisms in A level)
- but no nuclei ever destroyed or created
