Nursing Elites

1. Which is a property of an ionic compound?

• A. Low melting point
• B. Poor conductivity
• C. Shared electrons
• D. Crystalline shape

Correct answer: D

Rationale: Ionic compounds are composed of positively and negatively charged ions that are held together by strong electrostatic forces. These ions arrange themselves in a repeating pattern to form a stable and orderly structure known as a crystalline shape. This is a characteristic property of ionic compounds, making choice D the correct answer. Choices A, B, and C are incorrect because ionic compounds typically have high melting points, good conductivity in the molten or dissolved state, and do not involve shared electrons but rather the transfer of electrons between atoms.

2. What form of radiation is composed of electrons traveling at around 16,000 km/sec?

• A. Alpha radiation
• B. Beta radiation
• C. Gamma radiation
• D. Delta radiation

Correct answer: B

Rationale: Beta radiation is composed of high-energy electrons (β- particles) or positrons (β+ particles) traveling at considerable speeds. In this case, the electrons traveling at around 16,000 km/sec align with the characteristics of beta radiation, making it the correct choice. Alpha radiation consists of helium nuclei, gamma radiation is electromagnetic radiation of high frequency, and delta radiation is not a recognized form of radiation, making them all incorrect choices.

3. Cobalt-60 has a half-life of 5 years. If you start with 20 g of cobalt-60, how much is left after 10 years?

• A. 15 g
• B. 10 g
• C. 5 g
• D. 2.5 g

Correct answer: C

Rationale: Cobalt-60's half-life of 5 years means that after 5 years, half of the initial amount remains. Therefore, after 10 years, a quarter (half of a half) of the initial amount will remain. Starting with 20 g, after 10 years, 5 g of cobalt-60 will be left. Choice A (15 g) is incorrect because it assumes a linear decrease, not considering the exponential decay characteristic of radioactive substances. Choice B (10 g) is incorrect as it overlooks that after 10 years, more decay has occurred. Choice D (2.5 g) is incorrect as it represents only an eighth of the initial amount after 10 years, not a quarter.

4. What is the correct name of MgO?

• A. Manganese oxide
• B. Magnesium oxide
• C. Magnesium oxate
• D. Magnesium hydroxide

Correct answer: B

Rationale: The correct name of MgO is Magnesium oxide. Mg represents the chemical symbol for magnesium, and O represents the chemical symbol for oxygen. When these elements combine, they form magnesium oxide. Option A, Manganese oxide, is incorrect as it refers to a compound of manganese and oxygen, not magnesium. Option C, Magnesium oxate, is not a valid chemical compound name. Option D, Magnesium hydroxide, refers to a different compound consisting of magnesium, oxygen, and hydrogen.

5. How many neutrons are in an atom of carbon-12?

• A. 2
• B. 4
• C. 6
• D. 24

Correct answer: C

Rationale: An atom of carbon-12 has 6 neutrons. The atomic number of carbon is 6, representing the number of protons. The atomic mass of carbon-12 is 12. To find the number of neutrons, subtract the atomic number from the atomic mass: 12 - 6 = 6 neutrons. Choice A, 2, is incorrect as it does not reflect the correct calculation for neutrons in carbon-12. Choice B, 4, is incorrect as it does not match the correct number of neutrons in carbon-12. Choice D, 24, is incorrect as it is significantly higher than the actual number of neutrons in carbon-12.

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