CC3- Atomic Structures Flashcards
1
Q
How did John dalton and JJ thompson describe atoms?
A
- John Dalton claimed that atoms were tiny hard spheres that made up the different elements
- However, JJ Thompson concluded that atoms were not solid spheres. He claimed that atoms must have even smaller negatively charged particles (electrons). He theorised the plum pudding model.
2
Q
What was JJ Thompson’s plum pudding model?
A
- The plum pudding model had a positively charged base with negative electrons scattered throughout it
- JJ, Thompson’s plum pudding model was proven wrong by Ernest RutherFord
3
Q
What was Ernest Rutherfords finding of the atom?
A
- When conducting an experiment, Rusan food fired fired positively, charged alphabet the particles at a thin sheet of gold from the plum pudding model, they expected the particles to pass straight through considering the positive charge of the atom was thought to be spread out all across the atom
- However, while most of the particles did go through the foil, some were deflected, so this showed the pumping model could not be right
- Rutherford then said that in within an atom, there would be a tiny positively charged nucleus at the centre, surrounded by a cloud of negative electrons and he also said that most of the atom was empty space
4
Q
What is the Bohr model of the atom?
A
- from Rutherfords findings, If electrons were in a cloud around the nucleus, they would be attracted to the nucleus, therefore causing the atom to collapse.
- So Bohr suggested that the electrons only existed in fixed orbits on shells that surrounded the nucleus
5
Q
What are atoms made up of?
A
- atoms are made up of three subatomic particles: protons, neutrons and electrons.
6
Q
What is the relative mass and relative charge of a proton?
A
Relative mass: 1
Relative charge: +1
7
Q
What is the relative mass and relative charge of a neutron?
A
- relative mass: 1
- Relative charge: 0
8
Q
What is the relative mass and the relative charge of an electron?
A
- Relative mass: almost 0
- Relative charge: -1
9
Q
What is the nucleus?
A
- it is in the middle of the atom
- It contains protons and neutrons
- It has a positive charge because of the protons
- Almost all of the mass of the atom is concentrated in the nucleus
- Compare to the overall size of the atom nucleus is tiny
10
Q
What are electrons?
A
- Electrons move around the nucleus in electron shells
- They are negatively charged
- The electron particles are tiny, but their shells cover a lot of space
11
Q
Why are atoms neutral?
A
- Atoms are neutral and have no charge because they have the same number of protons and electrons
- The charge on the electrons is the same size as the charge on a proton is there since the protons is plus and electrons are negative the opposite charges cancel out
- The neutrons have a charge of zero, so they are cancelled out
12
Q
On an element in the periodic table, what is the number above?
A
- The number above is the mass number
- This tells you the total number of protons and neutrons in the atom
13
Q
On an element in the periodic table, what is the number below?
A
- The number below is the atomic number
- The atomic number tells you how many protons an atom has
- In every isotope of an element, it will have the same number of protons
- since atoms are neutral, they will have the same number of protons and electrons. Therefore the atomic number also tells us the amount of electrons.
14
Q
How do you workout the number of neutrons in an atom?
A
- To workout the number of neutrons subtract the atomic number from the mass number
15
Q
What are isotopes?
A
- isotopes are different forms of the same element, which have the same number of protons (the atomic number), but different number of neutrons (different mass numbers)
