D. The number of electrons equals the atomic number for a neutral element. Each number after the letter refers to the number of electrons in that shell. So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.
Answer:
b. primitive cubic < body-centered cubic < face-centered cubic
Explanation:
The coordination number is defined as <em>the number of atoms (or ions) surrounding an atom (or ion) in a crystal lattice</em>. Its value gives us a measure of how tightly the spheres are packed together. The larger the coordination number, the closer the spheres are to each other.
- In the <u>primitive cubic</u>, each sphere is in contact with 6 spheres, so its <u>coordination number is 6</u>.
- In the <u>body-centered cubic</u>, each sphere is in contact with 8 spheres, so its <u>coordination number is 12</u>.
- In the <u>face-centered cubic</u>, each sphere is in contact with 12 spheres, so its <u>coordination number is 12</u>.
Therefore, the increasing order in density is the primitive cubic first, then the body-centered cubic, and finally the face-centered cubic.
answer: -230kJ
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