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Question
Write down the electronic configuration of the following elements from the given atomic numbers. Answer the following question with explanation.
11Na, 15P, 17Cl, 14Si, 12Mg Which of these has largest atoms?
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Solution
11Na, 15P, 17Cl, 14Si, 12Mg
Electronic configuration of the following elements is:
11Na = 2,8,1
15P = 2,8,5
17Cl = 2,8,7
14Si = 2,8,4
12Mg = 2,8,2
11Na has largest size among these because according to the trend, atomic radius decreases as we move from left to right in a period of the periodic table. The atomic number of elements increases which means the number of protons and electrons in the atoms increases. Due to large positive charge on the nucleus, the electrons are pulled closer to the nucleus and the size of atom decreases.
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