What number on the periodic table indicates the energy level of an atoms valence electrons?

Answer 1

The number beside the letter represents the energy level.

The letter represents the sub level.

The exponent represents the number of electrons in the sub level.

So in the case of:

1s^2

1 is the energy level;

S is the sub level;

^2 is the number of electrons in the sub level.

Answer 2

The different rows of elements are called periods. The period number of an element signifies the highest energy level an electron in an atom of that element occupies (in the unexcited state). The number of elements in a period increases as one moves down the Periodic Table because as the energy level of the atom increases, the number of energy sub-levels per energy level increases.

Answer 3

The period gives you the outermost shell, the shell with the highest principal quantum number.. However the valence electrons may also include electrons in a

lower shell. The aufbau principle shows which order the elements orbitals are filled by electrons. For the transition elements in period three the 3d orbital is higher in energy than the 4s so the 3d electrons should also be considered to be valence electrons. An example is iron which loses 3 electrons from the 4s and 3d orbitals.

Answer 4

The rows in a periodic table are called "Periods".