Which of the following is the atomic number of an atom that has 12 protons and 12 neutrons?
A. 24
B. 12
C. 1
D. 144
The atomic number of an atom is equal to the number of protons in its nucleus.
In this case, the atom has 12 protons, so its atomic number is 12.
Choice A, 24, is not the correct answer because it represents the sum of the number of protons and neutrons in the atom’s nucleus, which is known as the mass number.
Choice C, 1, is not the correct answer because it does not represent the number of protons in the atom’s nucleus.
Choice D, 144, is not the correct answer because it represents the square of the mass number and does not represent any property of the atom.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: Which of the following structures is present in both prokaryotic and eukaryotic cells?
A. Cell membrane
B. Golgi apparatus
C. Chloroplasts
D. Endoplasmic reticulum
Answer Explanation
The cell membrane is present in both prokaryotic and eukaryotic cells.
The cell membrane is a thin, flexible barrier that surrounds all cells and separates the inside of the cell from the outside environment.
It is composed of a lipid bilayer and regulates the movement of substances into and out of the cell.
Choice B is incorrect because the Golgi apparatus is not present in prokaryotic cells.
The Golgi apparatus is an organelle found in eukaryotic cells that is involved in modifying, sorting, and packaging proteins and lipids for transport to other parts of the cell or to be secreted outside the cell.
Choice C is incorrect because chloroplasts are not present in prokaryotic cells.
Chloroplasts are organelles found in plant cells and some algae that are responsible for photosynthesis.
Choice D is incorrect because the endoplasmic reticulum is not present in prokaryotic cells.
The endoplasmic reticulum is an organelle found in eukaryotic cells that is involved in protein synthesis and lipid metabolism.
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Q #2: Which of the following results in osteoporosis?
A. An increase in osteocyte activity while osteoclast activity continues at expected levels.
B. A decline in osteoclast activity while osteoblast activity continues at expected levels.
C. An increase in osteocyte activity while osteoblast activity reduces.
D. A decline in osteoblast activity while osteoclast activity continues at expected levels.
Answer Explanation
A decline in osteoblast activity while osteoclast activity continues at expected levels results in osteoporosis.
Osteoporosis is caused by an imbalance between the functioning of osteoclast and osteoblast cells.
Osteoblasts are responsible for forming new bone, while osteoclasts break down old bone.
If osteoblast activity declines while osteoclast activity continues at expected levels, this means that more bone is being broken down than is being formed, leading to a loss of bone density and an increased risk of osteoporosis.
Choice A is incorrect because an increase in osteocyte activity would not result in osteoporosis.
Osteocytes are mature bone cells that maintain the mineral concentration of the bone matrix.
Choice B is incorrect because a decline in osteoclast activity would not result in osteoporosis.
Osteoclasts break down old bone, so a decline in their activity would mean that less bone is being broken down.
Choice C is incorrect because an increase in osteocyte activity would not result in osteoporosis.
As mentioned earlier, osteocytes are mature bone cells that maintain the mineral concentration of the bone matrix.
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Q #3: In a phase diagram, which of the following is the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously?
A. Triple point
B. Critical temperature
C. Critical point
D. Absolute zero
Answer Explanation
Triple point.
In a phase diagram, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously is the triple point.
The triple point is a unique point on a phase diagram where the three states of matter (solid, liquid, and gas) can coexist in equilibrium.
At the triple point, the temperature and pressure of the substance are fixed.
Option B, critical temperature, is the temperature at which a gas cannot be liquefied, regardless of the pressure applied.
It is a characteristic property of a substance and is typically higher than the boiling point of the liquid at standard pressure.
Option C, critical point, is the point on a phase diagram where the liquid and gas phases of a substance become indistinguishable.
At the critical point, the distinction between the liquid and gas phases disappears, and the substance becomes a supercritical fluid.
Option D, absolute zero, is the theoretical temperature at which all matter has zero thermal energy.
At absolute zero, all substances are in their solid state, but it is not relevant to a phase diagram, as it is a temperature where no transitions between states occur.
In summary, the term used for a substance held at a temperature and pressure where the solid, liquid, and gaseous states of a substance exist simultaneously in a phase diagram is the triple point, whereas the other options provided are not relevant or are characteristic properties of substances in different contexts.
