Shadow Power 24

In an atom, around the nucleus, there are some circular stable axes on which electron moves around. They are called energy level or orbit.

Chemically similar every three elements have atomic mass such that the middle one has the atomic mass of about the average of the other two – this is the Triads Law.

The change of material property with the successive change of period and group in the periodic table is termed as the periodicity of elements.

The electrons at the outermost principal energy level of an element are called the valence electrons of that element.

Elements of Group-3 to Group-12 of the periodic table are known as transition elements.

If a solid substance converts to a gaseous substance due to the application of heat and converts to solid directly due to cooling, then the substance is called volatile substance and the process is called sublimation.

The formula of baking powder is NaHCO3.

Arranging the elements based on their molecular weight, their physical and chemical properties are noticed to periodically reoccur.