Chemistry Hesi A2 - Nurselytic

Correct Answer: B

Rationale: In the compound NH3, nitrogen is bonded to three hydrogen atoms. Hydrogen is always assigned an oxidation state of +1. Since the overall charge of NH3 is zero, the oxidation state of nitrogen must be -1 to balance out the hydrogen's +1 oxidation state.
Therefore, the correct oxidation state of the nitrogen atom in NH3 is -1.
Choice A (-3) is incorrect because it does not account for the electronegativity of hydrogen.
Choice C (+1) and
Choice D (+3) are incorrect as the nitrogen atom in NH3 needs to balance the +1 oxidation state of each hydrogen atom, resulting in a total of -3 to maintain the compound's charge neutrality.

Correct Answer: C

Rationale: Atoms with the largest atomic radius are located at the bottom of their group on the periodic table. This is because atomic radius increases down a group due to the addition of more energy levels or shells of electrons. As you move down a group, the outermost electrons are further away from the nucleus, leading to an increase in atomic radius.
Choice A 'At the top of their group' is incorrect because atomic radius decreases going up within a group.
Choice B 'In the middle of their group' is incorrect as the atomic radius generally increases as you go down a group, not in the middle.
Choice D 'Along the right-hand side' is incorrect because atomic radius tends to decrease from left to right across a period on the periodic table due to increased nuclear charge and effective nuclear charge.

Correct Answer: A

Rationale: A blood pH of 3 is significantly low, indicating a strong acidity level. The normal blood pH range is 7.35 to 7.45; therefore, a pH of 3 is far below the normal range, showing a highly acidic condition in the blood sample.
Choice B is incorrect because a pH of 3 is not basic at all.
Choice C is incorrect as a pH of 3 is not weakly acidic but strongly acidic.
Choice D is wrong as a blood pH of 3 does not indicate a weakly basic condition.

Correct Answer: A

Rationale: In the solid state, you would expect a nonmetal to be brittle. Nonmetals generally lack the malleability and ductility of metals, which makes them prone to being brittle and easily fractured under stress. This property is due to the lack of metallic bonding in nonmetals, which results in a more rigid and less flexible structure.


Choice B, 'lustrous,' is incorrect because nonmetals typically do not exhibit a shiny or reflective surface like metals do.
Choice C, 'malleable,' is also incorrect as nonmetals lack the ability to be hammered or rolled into thin sheets like metals.
Choice D, 'conductive,' is incorrect since nonmetals are generally poor conductors of electricity compared to metals.

Correct Answer: A

Rationale: Ozone (O3) is a triatomic allotrope of oxygen. It differs from the common diatomic oxygen molecule (O2) by having three oxygen atoms bonded together. Ozone is known for its protective role in the Earth's atmosphere, absorbing most of the Sun's harmful ultraviolet radiation. Water (H2O) is a compound composed of two hydrogen atoms and one oxygen atom. Acidic oxide and carbon dioxide are not triatomic allotropes of oxygen. Carbon dioxide consists of one carbon atom and two oxygen atoms, while acidic oxides refer to compounds where oxygen is bonded with other elements to form oxides, and they are not allotropes of oxygen.