Of the following, the most nonmetallic element is of the following, the most nonmetallic element is s se cl p br

Cl is the most non-metallic element.

Explanation:

Non-metals are the substance that tend to gain electron(s) in order to complete their octet.

When we move across a period in periodic table then there will be increase in electronegativity of the elements and also there will be decrease in size of elements.

Since, elements S and Se belongs to group 16. Whereas P is a group 15 element and both Cl and Br belongs to group 17.

Also, when we move down the group there will be increase in size of elements due to increase in number of shells. As a result, force of attraction decreases between the nucleus and valence shell of an element.

This means that smaller is the size of a non-metal more will be its ability to gain an electron. Hence, more will be its non-metallic character.

Out of Cl and Br, Cl is smaller in size and more electronegative than Br.

Thus, we can conclude that out of the given options Cl is the most non-metallic element.

the correct answer is boyle

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.