What do the periods and rows in the periodic table signify

Question

so, is the periods that go from left to right show how much reactive the element is? and do the rows signify the atomic mass?

Answer 1

As you go down a group, the potential energy levels are increasing.

As you go across a period, the valence is increasing.

Hydrogen is very reactive because it has 1 valence electron so it can easily give it away or take another electron to form a stable ion.

Helium is at the right because it's orbitals are full of electrons.

The first orbital 1s2 only holds 2 electrons, and Helium has 2 electrons which are occupying those orbitals.

On another note about periodic table trends,

As you go UP reactivity increases as you go RIGHT reactivity increases.

Therefore Flourine (F) is the most reactive element

Answer 2

As you go from left to right across a period, the atomic radius decreases as electronegativity increases.

The alkali metals are row 1 on the periodic table (furthest to the left) and most reactive.

For more periodic table trends, go here:

http://dl.clackamas.cc.or.us/ch104-06/pe...

Answer 3

i think they organize it bye what i think is the atomic number good luck i hope it helped

Answer 4

In the periodic table, periods and rows are the same. The columns are called groups.

The groups show elements with a similar valence structure. The elements on the very left, for example, have 1 valence electron. This electron configuration tends to make them very reactive. The groups towards the right tend to have more valence electrons, but the orbitals are slowly filling up, meaning the elements at the extreme right have stable orbitals. The groups themselves have reactivity periodicity, but that depends on the group. The alkail metals, for example, get more reactive down the group, whereas the halogens are more reactive up the group.

Periods signify the number of shells. In period one, the elements have only one shell. In period 2, the elements have 2 shells, meaning they can have more electrons.

Answer 5

Ive been taught that the periods show how many outer shells the atom has, and the rows signify how many electrons are in the outer shell.

Answer 6

As you read from left to right, the number of electrons that are in the valence shell increase.  The noble gases have filled valence shells thus, they are stable whereas Hydrogen only has one electron in its valence shell, thus making it volitile