Since this atom has a total of eight electrons, it also has eight protons ... After the third energy level has 8 electrons, the next electron goes into the fourth level. 4th Period: Potassium and ...

Calcium is found on the left of the periodic table, surrounded by other metals. Calcium has the usual properties of a metal. For example it is a good conductor of heat and electricity. Gethin ...

The positive and negative ions attract each other and form the ionic compound sodium chloride. One calcium and two chlorine atoms are near each other. An electron from each atom feels the attraction ...

who discovered that the atomic number (the number of protons in the nucleus of an atom) is the fundamental property that determines an element's position in the periodic table, rather than its ...