Which of the following represents a pair of isotopes? Select one: a. 146C, 147N b. 11H, 21H c. 136C, 147N d. O2, O3 e. 3216S, 3216S2- Check

B

Explanation:

Isotopy is a phenomenon in which there exists two or more kind of atoms of the same element. These atoms have the same number of protons but different mass numbers. That is, they have the same atomic number but differ only by the number of neutrons in the nucleus of the atom. Now, let us apply this information to the options individually:

A. Is wrong, they are not the same element

B. Is correct. they both belong to the same element hydrogen. Infact, they are named protium and deuterium respectively

C is wrong they are not same element

D is wrong They are not elements at all

E. Is wrong, one is an element, the other is a molecule

we can conclude that the melting point of table salt is above room temperature (it's actually 801 deg c). the melting point of mercury must be below room temperature (- 39 deg c).

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: