Nursing Elites

1. What is the correct formula for sodium nitrate?

• A. NaNO
• B. Na NO
• C. NaNO₃
• D. Na NO₂

Correct answer: C

Rationale: The correct formula for sodium nitrate is NaNO₃. In this formula, 'Na' represents sodium, 'N' represents nitrogen, and 'O₃' represents three oxygen atoms. Sodium nitrate consists of one sodium ion (Na⁺) and one nitrate ion (NO₃⁻), which means the correct formula is NaNO₃. Choice A (NaNO) is incorrect as it lacks the subscript indicating the presence of three oxygen atoms. Choice B (Na NO) is incorrect as it includes a space between 'Na' and 'NO', which is not part of the standard chemical formula notation. Choice D (Na NO₂) is incorrect as it indicates a different compound with a nitrite ion (NO₂⁻) instead of nitrate ion.

2. If oxygen is in a compound, what would its oxidation number be?

• A. 2
• B. -2
• C. 0
• D. -1

Correct answer: B

Rationale: Oxygen typically has an oxidation number of -2 in compounds because it tends to gain electrons. This is due to its high electronegativity, which leads to oxygen attracting electrons towards itself in a chemical bond. Choice A (2) is incorrect because oxygen doesn't have a +2 oxidation number in compounds. Choice C (0) is incorrect as oxygen rarely has an oxidation number of 0 in compounds. Choice D (-1) is incorrect as oxygen's oxidation number in compounds is typically -2, not -1.

3. Which substance causes a drop to rapidly turn litmus dye from blue to red?

• A. Milk
• B. Sea water
• C. Ammonia
• D. Lemon juice

Correct answer: D

Rationale: Lemon juice is the correct answer as it is acidic in nature. Acids like lemon juice release hydrogen ions when dissolved in water, which causes litmus dye to change color from blue to red. Milk (Choice A) is neutral, sea water (Choice B) is slightly alkaline, and ammonia (Choice C) is a base. Therefore, these substances do not cause litmus dye to change from blue to red.

4. What charge do Group IIIA elements have?

• A. +1
• B. +2
• C. +3
• D. 0

Correct answer: C

Rationale: Group IIIA elements, also known as Group 13 elements, have a common oxidation state of +3. This is because they have three valence electrons and tend to lose these electrons to achieve a stable electron configuration, resulting in a +3 charge. Choice A (+1) and Choice B (+2) are incorrect because Group IIIA elements typically lose all three valence electrons to attain a stable configuration, leading to a +3 charge. Choice D (0) is incorrect as these elements do not gain electrons but rather lose them, resulting in a positive charge.

5. On the periodic table, where are atoms with the largest atomic radius located?

• A. At the top of their group
• B. In the middle of their group
• C. At the bottom of their group
• D. Along the right-hand side

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.

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