Classification of elements helps us to

study elements better in a systematic way

correlate the properties of elements with some fundamental properties of matter

reveal the relationship of various elements with each other

The atomic number of a few elements are 10 , 27 , 7 , 14 . Identify the elements.

The atomic number of a few elements are given the name of the elements are as follows: Atomic number 10 = Neon Atomic number 27 = Cobalt Atomic number 7 = Nitrogen Atomic number 14 = Silicon Note: The atomic number or proton number of a chemical element is the number of protons found in the nucleus of every atom of that element.

What do you mean by ionization energy? What are the factors which determine the magnitude of ionization of energy?

Ionization energy can be described as a measure of the difficulty in removing an electron from an atom or ion or the tendency of an atom or ion to surrender an electron. The more electrons that are lost, the more positive this ion will be, the harder it is to separate the electrons from the atom. The loss of electrons usually happens in the ground state of the chemical species. The factors that determine the magnitude of ionization energy are as follows: (i) Nuclear charge: Nuclear charge is essentially the electrostatic attraction that the positively charged protons exert on the outermost electrons. This is directly proportional to the number of protons present in the nucleus. (ii) Screening/Shielding effect: Screening or shielding effect refers to this reduction of the electrostatic force of attraction as the inner shell electrons “shield” the valence electrons from the full attractive force from the nucleus.

What are semimetals? Name any two semimetals.

Semimetals are a very small group of elements that are present in the periodic table, along the zig-zag line that is seen to distinguish metals from non-metals. They are found to have properties that are intermediate between metals and non-metals. For example, Boron B , Silicon Si , etc.