Which of the following best describes the term 'atomic radius'?

• A. The total number of protons and neutrons in an atom.
• B. The distance from the nucleus to the outermost electron in an atom.
• C. The energy required to remove an electron from an atom.
• D. The number of electrons in the outermost shell of an atom.

Answer: (B)

Verified step by step guidance

1. Understand that 'atomic radius' refers to a measure of size of an atom, specifically how far the outermost electrons are from the nucleus.
2. Recognize that the total number of protons and neutrons in an atom is called the 'mass number,' not the atomic radius.
3. Know that the energy required to remove an electron from an atom is called 'ionization energy,' which is different from atomic radius.
4. Identify that the number of electrons in the outermost shell is called the 'valence electrons,' which also differs from atomic radius.
5. Conclude that the best description of atomic radius is 'the distance from the nucleus to the outermost electron in an atom,' as it directly relates to the size of the atom.