C1.2 Atomic Structure Flashcards
Relative charge of a proton?
+1
Relative charge of a neutron?
0
Relative charge of an electron?
-1
Relative mass of a proton?
1
Relative mass of a neutron?
1
Relative mass of an electron?
0.005
Where in the atom are protons found?
In the nucleus
Where in the atom are neutrons found?
In the nucleus
Why is the nucleus of an atom positively charged?
Contains the protons (and neutrons which are neutral)
Why do atoms have no charge overall?
An equal number of protons and electrons = no charge overall
What are ions?
A charged atom due to protons & electrons not being equal which has a charge
What is an isotope?
Isotopes have similar chemical properties but different physical properties compared to the original atom
Describe how elements are arranged in the periodic table
Left to right/top to bottom in order of increasing atomic number and increasing atomic mass
Atomic number (Z)?
Number of protons in the nucleus of an atom (the bottom no.)
Mass number (A)?
The sum of protons and neutrons in the nucleus of an atom (the top no.)
What was Dalton’s theory?
All matter is indestructible atoms with distinct mass/properties. Atoms are tiny particles
What was Thompson’s experiment?
Cathode Ray tubes were used and they deflected negatively charged plates and were towards the positively charged plate - composed of negatively charged particles.
What was Rutherford’s expermient with Griger & Marsden?
Alpha particles were shot at thin pieces of gold leading to a fluorescent screen. Found out that the mass-energy is concentrated in the center - the nucleus.
What did Bohr discover?
Electrons exist in shells that have constant energy & orbit in fixed distances (called energy levels)
How to calculate the number of protons, neutrons & electrons in an atom?
- Protons = Atomic number
- Neutrons = Atomic number - Mass number
- Electrons =
Neutral charge:
Number of Protons
Positive charge:
More protons than electrons (dependent on the charge number)
Negative charge:
More electrons than protons
(dependent on the charge number)
Electron structure?
How electrons are arranged in an atom depends on the element
What is configuration?
Number of electrons in the rings (adding up to the total number)
How many electrons can the rings hold?
1st shell - up to 2
2nd & 3rd shell - up to 8
4th, 5th, 6th, 7th shell - up to 18
How is configuration written?
With the amount of electrons (in numbers) in order of the shell (inner to outer) eg. 2,5,7
