Knowledge recall

Created by

Shekinah Obare

Cards (35)

Atom 
The smallest part of an element that can exist
Element 
A substance made of only one type of atom
Compound
A substance made of two or more different atoms chemically bonded together in fixed proportions
Molecule 
A substance made of more than one atom chemically bonded together
Mixture 
Two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged.
State the type of mixture separated by filtration.
An insoluble solid in a liquid.
State the type of mixture separated by crystallisation.
A soluble solid from a solution.
State the type of mixture separated by simple distillation.
A solution containing two liquids or a solvent from a solid.
State the type of mixture separated by fractional distillation.
A mixture of more than two different solvents.
State the type of mixture separated by chromatography.
A mixture of solvents or solutions.
How was the atom described prior to the development of the atom?
As a tiny sphere that could not be divided.
What led to the development of the Plum Pudding Model?
The discovery of the electron.
What is the plum pudding model of the atom?
A ball of positive charge with negative electrons embedded into it.
What experiment led to the development of the Nuclear Model?
The alpha scattering experiment
What were the two conclusions from the alpha scattering experiment?
The mass of an atom was concentrated at the centre and the nucleus was positively charged.
How did Neils Bohr adapt the nuclear model?
By suggesting that electrons orbit the nucleus at specific distances.
What evidence supported Neils Bohr's adapted nuclear model?
The theoretical calculations of Bohr agreed with experimental observations.
How were protons discovered in the nucleus?
Later experiments led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge.
What was James Chadwick's contribution to the atomic model?
He provided the evidence to show the existence of neutrons within the nucleus.
State the three subatomic particles
Protons, neutrons, electrons.
State the relative charges of the subatomic particles
Protons: +1, neutrons: 0, electrons: -1
What is the atomic number of an atom?
The number of protons in an atom.
What do all atoms of an element have in common?
The same atomic number (number of protons).
How can you find out how many protons are in an atom?
The smaller number on an element in the Periodic Table is the atomic number.
Explain how you can tell how many electrons are in an atom?
The number of protons equals the number of electrons in an element because atoms are neutral.
State the order of size of the following from smallest to largest: Nucleus,
Electron, Atom, Molecule
Electron, nucleus, atom, molecule
State the relative masses of the subatomic particles
Proton: 1, neutron: 1, electron: 0
What is the mass number of an atom?
The sum of protons and neutrons in an atoms nucleus.
Where can you find the mass number in the Periodic Table?
The larger number on an element in the Periodic Table is the mass number.
How do you calculate the number of neutrons in an atom?
Neutron number = Mass number - atomic number
What is an isotope?
Atoms of the same element with the same number of protons but a different number of neutrons in the nucleus.
Two isotopes are Cl-35 and Cl-37. Their atomic number is 17. Compare the two isotopes. 
Both have 17 protons and 17 electrons. Cl-35 has 18 neutrons. Cl-37 has 20 neutrons.
What is relative atomic mass? 
It is an average value that takes account of the abundance of the isotopes of the element.
The abundance of Cl-35 is 75% and Cl-37 is 25%, explain why the relative atomic mass of Cl is 35.5. 
The relative atomic mass is closer to 35 because Cl-35 is more abundant than Cl-37.
Which energy level is filled first in an atom?
The lowest energy level