Question

1. a student compares diamond, graphite, and two different $\ce{c4h10}$ molecules. which classification is correct? 1

a. all are allotropes because they involve carbon.
b. diamond and graphite are isomers; the $\ce{c4h10}$ compounds are allotropes.
c. all are isomers because they contain carbon atoms.
d. diamond and graphite are allotropes; the $\ce{c4h10}$ compounds are isomers.

1. which conclusion was developed as a result of the gold foil experiment? 1

a. atoms are mostly empty space.
b. all atoms are hard, indivisible spheres.
c. atoms have different volumes.
d. all atoms have the same volume.

1. which two particles each have a mass approximately equal to one atomic mass unit? 1

a. positron and proton
b. positron and electron
c. neutron and electron
d. neutron and proton

1. an excited potassium atom emits a specific amount of energy when one of its electrons moves from 1

a. the first shell to the fourth shell
b. the second shell to the fourth shell
c. the fourth shell to the fifth shell
d. the fourth shell to the second shell

1. which list of elements includes a metal, a metalloid, and a noble gas? 1

a. $\ce{rb}$, $\ce{cl}$, $\ce{ne}$
b. $\ce{sr}$, $\ce{si}$, $\ce{rn}$
c. $\ce{rn}$, $\ce{cl}$, $\ce{ne}$

Explanation:

Question 83

Allotropes are different forms of the same element (like diamond and graphite for carbon). Isomers are compounds with the same molecular formula but different structures (like different \( \text{C}_4\text{H}_{10} \) molecules). So diamond and graphite are allotropes, and \( \text{C}_4\text{H}_{10} \) compounds are isomers.

The gold foil experiment (Rutherford's) showed that most of the alpha particles passed through (atoms are mostly empty space), some deflected (nucleus is positive and dense). Option a matches this conclusion.

A neutron and a proton both have a mass approximately equal to 1 atomic mass unit (amu). Electrons have negligible mass, and positrons have the same mass as electrons. So option d is correct.

Answer:

d. Diamond and graphite are allotropes; the \( \text{C}_4\text{H}_{10} \) compounds are isomers.

Question 84