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Periodic table
GCSE chemistry and combined chemistry
Question | Answer |
---|---|
What is the atomic number of an atom? | The number of protons in an atom |
What can the period tell you about the electrons in an atom? | How many shells an atom has. E.g. carbon is in the second period so has two shells |
Why did Mendeleev put some elements in groups? | Because they had similar chemical properties (e.g. they reacted violently with water) |
What did Mendeleev put the elements in order of? | Increasing atomic mass |
How is the modern periodic table organised? | In order of increasing atomic number |
Why did Mendeleev leave gaps in his periodic table? | For elements that had not been discovered yet |
What are groups in the periodic table? | The columns, numbered 1, 2, 3, 4, 5, 6, 7, 0 |
What can the group tell you about the electrons in an atom? | How many electrons in the outer shell. E.g. carbon is in group 4 so has 4 electrons in the outer shell |
How are the electrons arranged in atoms? | Orbiting the nucleus in shells |
Where are the metals found on the periodic table? | on the left hand side |
How many electrons does calcium have? | 20 (same as atomic number!) |
How many electrons does silicon have? | 14 (same as atomic number!) |
How are the electrons in sulphur arranged? | 2.8.6 (18 electrons total) |
How are the electrons in magnesium arranged? | 2.8.2 (12 electrons total) |
How many electrons are in the outer shell of boron? | 3 (it is in group 3!) |
How many electrons are in the outer shell of phosphorous? | 5 (it is in group 5!) |
How many electrons are in the outer shell of sodium? | 1 (it is in group 1!) |
An element has three shells and three electrons in the outer shell. What element is it? | Aluminium (group 3, period 3 |
How many electrons are in the outer shell of Gallium? | 3 (it is in group 3!) |
How many electrons can go in the first shell? How many in the second shell? | 2 = 1st shell, 7 = second shell |