What is common about the elements of a period? Select all that apply. They have the same number of electron energy levels. They have similar chemical characteristics. They have similar physical characteristics. They transition from a metal to noble gas.

A period is the horizontal row of elements in the periodic table and they are numbered from one to seven. In the same period, atomic number increases from left to right. Elements in the same period have the same number of electron energy levels and they transition from a metal to noble gas.

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RomeliaThurston RomeliaThurston · Answer 2 · 2019-05-07T07:50:25+02:00

Answer: The correct statements are they have the same number of electron energy levels and they transition from a metal to noble gas.

Explanation:

Elements are arranged in 7 periods and 18 groups in a periodic table.

Elements that are arranged in same group have same number of valence electrons and hence show similar chemical properties.

Elements that are arranged in same period have same number of energy levels. In a periods, first metals come, then non-metals and a period ends with a noble gas always.

Hence, the correct statements are they have the same number of electron energy levels and they transition from a metal to noble gas.