Charge It! Electrons are the negatively charged particles of atom. Together, all of the electrons of an atom create a negative charge that balances the positive charge of the protons in the atomic nucleus. Electrons are extremely small compared to all of the other parts of the atom.

The electrons are most responsible for the chemical properties of the atom and are located outside of the nucleus.

The chemical properties of the atom are determined by the number of protons, in fact, by number and arrangement of electrons. The configuration of these electrons follows from the principles of quantum mechanics.

Sulfur is in the same Group as oxygen and one Period lower, so its outer electrons occupy orbitals from the n = 3 level while oxygen’s outer electrons occupy orbitals from the n = 2 level. Consequently for the neutral atoms, S would be larger than O.

Answer. Sodium(Na) is bigger than Magnesium(Mg) because the atomic no. of Na is 11 whereas the atomic number of Magnesium is 12 so the atom of Magnesium shrinks more than sodium .

As an example, potassium (K) has a larger average atomic radius (220 pm)than sodium (Na) does (180 pm). The potassium atom has an extra electron shell compared to the sodium atom, which means its valence electrons are further from the nucleus, giving potassium a larger atomic radius.

As Br is smaller than Cl; therefore, Br- have a smaller ionization energy than Cl-. In short, since the outermost electron in bromine is farther from the nucleus than the outermost electron in chloride, it takes less energy to remove the outermost electron in bromide.

Br– has 35 protons and 36 electrons. Rb+ has has 37 protons and 36 electrons. These are isoelectronic ions. Br– is the larger ion.