PDF chapter test TRY NOW
1. An atom has electronic configuration 2, 8, 7.
(a) What is the atomic number of this element ?
(a) What is the atomic number of this element ?
2. Where do you think should hydrogen be placed in the Modern periodic table?
Answer variants:
Hydrogen element has been placed at the top of group 2.
Hydrogen element has been placed at the top of group 3.
Hydrogen element has been placed at the top of group 1.
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