Which statement is true of unstable isotopes?

a)nuclei of light elements are very unstable. b)the nuclei of atoms that are the most unstable have proton to neutron ratios of 1 to 1.c)an unstable atom is an atom that has enough binding energy to hold the nucleus together permanently. d)an unstable isotope is one that undergoes spontaneous nuclear decay and is referred to as a radioisotope.

The correct answer is Option D.

Explanation:

Unstable isotopes are defined as the isotopes which have excess of neutrons as compared to the stable form of the nucleus of an atom.

These isotopes attain stability by undergoing a spontaneous nuclear decay. The isotopes which are unstable have another name and are known as radioactive isotopes or radioisotopes.

These isotopes undergoes decay by 4 processes: Alpha decay, beta decay, gamma emission and positron decay.

Hence, the correct answer is option D.

in chemistry, adhesion and cohesion are attractive forces that exist between molecules. they hold the molecules together from each other. they are different in that adhesive force exists between molecules of different substance while cohesive force happens between molecules of same substance.

adhesion between water and glass causes water molecules at the edge of water and glass interface to climb up the wall in a narrow glass tube. this is called capillary action. cohesion is what gives glass its shape and causes water to form a droplet.