Question

question 13
a crystalline solid, has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy.
true
false

question 14
material science... (choose all that apply)
it is the study of noble gasses and their structure.
is responsible for inventing plastic.
it is the study of liquids and their useful properties.
is an interdisciplinary field.
is the study of properties and structure of materials.

question 15
electrons exist at energy levels that form shells around the nucleus.
true
false

Explanation:

Analyze crystalline solid melting behavior

Crystalline solids have highly ordered, repeating microscopic structures. Because the atoms, ions, or molecules are arranged in a regular, uniform lattice, the intermolecular forces holding them in place are identical throughout the crystal. Consequently, when heat is applied, all these equivalent bonds break at the exact same temperature, resulting in a sharp, precise melting point.

Define material science characteristics

Material science is a broad discipline. We evaluate each option:

• It is the study of noble gasses and their structure: Incorrect, as noble gases are not materials in the structural sense.
• Is responsible for inventing plastic: Incorrect, synthetic polymers were primarily developed by organic chemists (e.g., Leo Baekeland).
• It is the study of liquids and their useful properties: Incorrect, this is fluid mechanics or rheology.
• Is an interdisciplinary field: Correct. Using the Interdisciplinary Fields knowledge point, material science integrates chemistry, physics, and engineering.
• Is the study of properties and structure of materials: Correct, this is the fundamental definition of the field.

Evaluate electron energy levels and shells

According to modern atomic theory, electrons occupy specific, quantized energy levels. These discrete energy levels correspond to electron shells surrounding the positively charged nucleus. Therefore, the statement is correct.

Answer:

Question 13

• (A) True (Correct answer)
• (B) False

Question 14

• (A) It is the study of noble gasses and their structure.
• (B) Is responsible for inventing plastic.
• (C) It is the study of liquids and their useful properties.</mcq-correct>
• (D) Is an interdisciplinary field. (Correct answer)
• (E) Is the study of properties and structure of materials. (Correct answer)

Question 15

• (A) True (Correct answer)

<mcq-option>(B) False