Question

Explain the important distinctions between each pair of terms:

 (a) cathode rays and X-rays

 (b) protons and neutrons

 (c) nuclear charge and ionic charge

 (d) periods and groups of the periodic table

 (e) metal and nonmetal

 (f) the Avogadro constant and the mole

 

Answer 1

(a)

Cathode rays are beams of electrons being generated from a negatively charged surface (cathode) moving to a positively charged surface (anode). X-rays are high energy photons, which are typically generated when the high energy beam of electrons impinges on the anode.

 

(b)

Protons and neutrons are both fundamental particles that make up an atom’s nucleus.

Protons are positively charged and neutrons have no charge.

 

(c)

Nuclear charge is determined by the numbers of protons in the nucleus. Ionic charge is determined by the difference between the number of protons and electrons in the atom.

 

(d)

Periods are horizontal rows in the periodic table, while groups are vertical columns.

 

(e)

Metals are generally characterized by their malleability, ductility, and ability to conduct electricity and heat well. Nonmetals are generally brittle and nonconductive.

 

(f)

The Avogadro constant is the number of elementary entities (atoms, molecules, etc.) in one mole of a substance. A mole is the amount of a substance that contains the same number of elementary entities as there are atoms in exactly 12 g of pure carbon-12.