Isotopes (Cambridge (CIE) A Level Chemistry): Flashcards

Isotopes are atoms of the same element that have the same number of protons and electrons, but a different number of neutrons. They have the same atomic number but different mass numbers.

False.

Isotopes of the same element have the same atomic number (same number of protons) but different mass numbers because they contain different numbers of neutrons.

Isotopes are named using the chemical symbol (or element name) followed by a dash and the mass number. For example, carbon-12 and carbon-14 are isotopes of carbon with 6 and 8 neutrons respectively.

Isotopes of the same element have the same chemical properties but different physical properties.

Isotopes have the same number of electrons and the same electron configuration. Because chemical behaviour is determined by electrons (especially those in the outer shell), all isotopes of an element react in the same way.

False.

Isotopes have different numbers of neutrons, so they have different masses. This leads to differences in density and relative atomic mass, even though their chemical properties are identical.

Isotopes differ in the number of neutrons, which changes the nuclear mass without affecting charge. This leads to different relative atomic masses, densities and behaviour in processes such as mass spectrometry.

Chlorine-35 and chlorine-37 are isotopes of chlorine. They have the same atomic number of 17 but different mass numbers (35 and 37).

A neutral carbon-14 atom has:

1. Protons: 6 (= atomic number)

2. Neutrons: 8 (= 14 − 6)

3. Electrons: 6 (neutral atom, so electrons = protons)