EXAM Science Flashcards
What’s in the Nucleus
Protons and Netrons
What is an Atom
Atoms are the smallest particle of a substance that can still exist and still be that substance
What are shells and what are they also known as?
Are electrons grouped around the nucleus in regions, they are also known as energy levels
Neutral atoms are…
Atoms that have the same amounts of protons as electrons. All atoms are neutral
Atomic number
It is equal to the number of protons
Mass number
Is equal to the number of protons added to the number of neutrons
How many elements in periodic table
111
What are the 2 settings of the periodic table
Groups - Columns
Periods - Rows
How many elements found on earth
92
What are groups and what are the names of group 1,2,17 and 18
Groups are vertical columns that show how many electrons in the outer shell and so they all have similar chemical properties. Group 1 are alkali metals Group 2 are alkaline earth metals Group 17 are halogens Group 18 are noble gases
Element
A substance that contains only 1 type of atom
Compound
Atoms are tightly blinded together with more substances
How are compounds separated
Electricity, fire, mixing it with other compounds
Mixtures
2 or more elements together but not combined
How are mixtures separated
Standing and decanting, heating and evaporating and filtration and magnets
Physical change
A change of a substance but no bonds are broken - can tell if it goes back to it’s original state
Chemical properties
A change that breaks the bonds between other elements - can tell if new element is formed and difficult to reverse
How can you tell chemical change
Cloudiness appears in liquid or gas, odour, bubbles, increase or decrease temperature, light or flame, change in colour but certain is to detect new element
Rust
It is an example of corrosion a flaking substance that forms
What are isotopes?
They are atoms with the same number of protons, but a different number of neutrons. They have the same atomic number but different mass numbers
Show the isotopic representation
Mass Number-> a
X <—- symbol
Atomic Number-> z
What are valence shells?
They are the outer shells, they can never have more than 8 electrons and are the easiest electrons to remove from the atom
How do you draw and write the electrons of an atom?
You draw them in pairs around the nucleus which shows either the elements symbol or the number of protons. You write them order from inner shell to outer, e.g. Carbon 2,4
How are elements ordered in the periodic table?
In increasing atomic number
What are periods?
They at horizontal rows that have the same number of shells. They are numbered 1-7
Know where the metals, non-metals, metalloids and transition metals are.
.
What is ionic bonding?
When an atoms loses or gains electrons in order to become more stable. Metals give away electrons and non-metals gain electrons.
What are cations and anions
When metals gives away electrons it becomes a cation as it is positive
When non-metals receive electrons it becomes an anion as it is negative