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CONTROL TASKS
1. How do the radii of atoms in periods and subgroups change?
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2. How many protons and neutrons are contained in the atom nucleus of Sn?
3. Write the full electronic formula of the elements 43Tc and 53I, and underline
the valence electrons.
4. Which atoms are isotopes, and which are isobars? , , , ,
(symbols А, B, C, D, E are as examples)
1
4
5
5. Specify the possible and impossible electron configurations: 1p , 2d , 3p ,
5
3
11
4s , 5d , 6p . Explain the answers.
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