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Chemistry Regents June 2010 - Question 02 |
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Written by The Chemistry Wizard
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Correct Answer: 3
Why: Carbon is an element located in group 14 of the periodic table. Like most other known elements, they are composed of a positively charged nucleus orbited by negatively charged electrons; therefore, the nucleus is the positively charged center of the atom. The nucleus is both positively charged and contains most of the mass of the atom, usually referred to as the atomic mass. The nucleus is composed of protons and neutrons for most elements, hydrogen being the exception, as its nucleus is composed of one proton and no neutrons.
Based on that information, the nucleus of carbon is composed of protons and neutrons. Carbon 12, the most common form of carbon, is composed of six (6) protons and six (6) neutrons, giving an atomic mass of approximately 12 (the mass of the electrons being negligible in comparison).
Answering the Question:
To answer this question, an understanding of atomic structure is necessary; although, knowledge of the structure of carbon is not necessary. The structure of the atom is such that it is composed of a central positively charged nucleus surrounded by orbiting negatively charged electrons. With that is mind, answer (4) and answer (2) would be immediately eliminated: answer (4) because the nucleus is not composed of protons and electrons, and answer (2) because neutrons have no charge and, therefore, would not be the only subatomic particles present in the nucleus of an atom. Answer (1) is also not possible as hydrogen is the only element with a nucleus that does not have neutrons associated with it. Therefore, the correct answer is answer (3), protons and neutrons.
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Last Updated on Tuesday, 07 June 2011 16:36 |
