Atomic Structure/ Periodic Table Flashcards
Where is the nucleus in an atom?
It is in the middle of the atom
Contains protons and neutrons
What is the charge of a nucleus?
Positive because of the protons
Why is the overall charge of an atom 0?
Because they have the same number of protons as electrons, the charges cancel each other out
What are the relative masses of protons, neutrons and electrons?
Proton 1
Neutron 1
Electron (very small) negligible
What does the atomic number show us?
How many protons there are
What does the mass number show us?
The total number of protons and neutrons in the atom
What is an element?
A substance made up of atoms that all have the same number of protons in their nucleus
What is an isotope?
Different forms of the same element, which have the same number of protons but a different number of neutrons
What is a common pair of isotopes?
Carbon-12 and carbon-13
How do you calculate the relative atomic mass? (Ar)
=sum of (isotopes abundance X mass number) / sum of abundances of all isotopes
What is a compound?
Substances formed from two or more elements, the atoms are held together by chemical bonds
What is a mixture?
Two or more elements or compounds mixed together (no chemical bonds)
How can mixtures be separated?
- filtration
- crystallisation
- simple distillation
- chromatography
- fractional distillation
What are examples of mixtures?
- air (oxygen, co2, nitrogen and argon)
- crude oil (mixture of hydrocarbons)
