Question

Li, si, na, p, he. Which of these elements belong to period 3? Explain

Answer 1

A period 3 element is one of the chemical elments in the third row (or period) of the period table of chemicals elements The periodic table is laid out in rows to illustrate recurring (periodic) trends in the chemical behaviour of the elements as their atomic number increases: a new row is begun when the periodic table skips a row and a chemical behaviour begins to repeat, meaning that elements with similar behavior fall into the same vertical columns

Answer 2

Answer:

As the elements Si,Na,P hve electrons in the 3 shells; K,L,M, these elements belong to period 3 as the no.of shells indicates the period no.