Why atomic and ionic size of elements of s and p block decreases along a period?

It is because on moving across the period, the atomic size decreases due to the increased nuclear charge and hence, ionization energy increases. On moving down the group the metallic character increases, whereas non-metallic character, decreases. It is because on moving down a group, the atomic size increases.

What is a substance that Cannot be decomposed into simpler substances during ordinary chemical reactions?

chemical element, also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed.

What is the longest word you can form from the symbols of the elements Write your answer on the space provided below?

Can you name the longest word made using periodic table symbols for the chemical elements? The answer in English is nonrepresentationalisms. This word is 23 letters long.

What rule or law is followed by atoms in attaining eight electrons in the outermost shell?

The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds.

Does atomic size increase or decrease down a group?

In general, atomic radius decreases across a period and increases down a group. Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital. This results in a larger atomic radius.

Why does size decrease across the periodic table?

Atomic size gradually decreases from left to right across a period of elements. This is because, within a period or family of elements, all electrons are added to the same shell. However, at the same time, protons are being added to the nucleus, making it more positively charged.

What type of substances make up almost 75 of all the elements?

The most common element in the universe, hydrogen, makes up almost 75 percent of all matter.

Why do some elements not follow the octet rule?

Some elements, most notably nitrogen, can form compounds that do not obey the octet rule. One class of such compounds are those that have an odd number of electrons. As the octet rule requires eight electrons around each atom, a molecule with an odd number of electrons must disobey the octet rule.

Which one of the following element will never obey octet rule?

Explanation: Hydrogen one of the element will never be obeyed octet rule.