Chemistry

The physical and chemical properties of the elements repeat periodically with their atomic number.

Methanal or the saturated aqueous solution of formaldehyde (40% by volume, 37% by weight) is known as 100% formalin which is mainly used to preserve dead animals.

Electron configuration is the distribution of electrons in various shells for any element. Such as electron configuration of Al is-Al(13)→ 2, 8, 3

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

According to Dalton’s atomic theory, the atom was indivisible and indestructible. But the discovery of two fundamental particles (electrons and protons) inside the atom, led to the failure of this aspect of Dalton’s atomic theory. It was then considered necessary to know how electrons and protons are arranged within an atom. For explaining this, many … Read more

Around the nucleus there are some circular stable axis on which electron moves around. These are called energy level or orbit.

Atoms of the same element having different mass number are called isotopes of each other.

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