Question

1. which statement correctly distinguishes allotropes from isomers? 1

a. allotropes are different elements; isomers are the same element.
b. allotropes and isomers both involve different molecular formulas.
c. allotropes are different forms of the same element; isomers are different compounds with the same molecular formula.
d. allotropes involve compounds, while isomers involve elements only.

1. which particles surround the nucleus of a neon atom? 1

a. electrons
b. neutrons
c. positrons
d. protons

1. which conclusion was proposed as a result of an experiment during which some alpha particles were deflected while passing through a thin sheet of gold foil? 1

a. atoms are hard, indivisible spheres.
b. atoms have small, dense, positive nuclei.
c. atoms contain negatively charged particles.
d. atoms have electrons with wavelike properties.

1. the mass of each proton and each neutron is approximately equal to 1

a. 1 g
b. 1 u
c. 1 ml
d. 1 mol

1. which statement describes the relationship between two electrons in an atom of magnesium in the ground state? 1

a. an electron in the first shell has the same amount of energy as an electron in the second shell.

Explanation:

Question 40

To distinguish allotropes and isomers: Allotropes are different structural forms of the same element (e.g., diamond and graphite for carbon). Isomers are different compounds with the same molecular formula (e.g., butane and isobutane). Option a is wrong (allotropes are same element). Option b is wrong (allotropes don't have molecular formulas as they are elements). Option d is wrong (allotropes are elements, isomers are compounds). So option c is correct.

In an atom, the nucleus contains protons and neutrons. Electrons are negatively charged particles that orbit (surround) the nucleus. Neutrons and protons are in the nucleus. Positrons are not part of a neutral neon atom's structure. So electrons surround the nucleus.

The gold foil experiment (Rutherford's) involved alpha particles (positive) hitting gold foil. Most passed through, some deflected. This showed atoms have a small, dense, positive nucleus (since positive alpha particles were deflected by positive nucleus). Option a is wrong (atom is not hard, indivisible sphere). Option c: the experiment didn't show negative particles directly. Option d: relates to electron wave - particle duality, not this experiment. So option b is correct.

Answer:

c. Allotropes are different forms of the same element; isomers are different compounds with the same molecular formula.

Question 41