Question

You analyze a sample of carbon and determine that \(6 \%\) of the carbon atoms in your sample have a mass number (atomic mass) greater than 12, (12 is the normal atomic mass of carbon). Based on these results, which of the following can you reasonably conclude? A. \(6 \%\) of the carbon sample is a different element B. \(6 \%\) of the sample is comprised of carbon isotopes C. \(6 \%\) of the sample is comprised of carbon ions D. \(94 \%\) of the sample is comprised of carbon radioisotopes E. \(94 \%\) of the sample contains covalent bonds

Short answer

B. 6% of the sample is comprised of carbon isotopes.

Step-by-step solution

Understand the Problem Statement

The problem states that 6% of the carbon atoms in the sample have a mass number greater than 12. Carbon normally has a mass number of 12, but some atoms have a higher mass number.

Identify the Concept

Carbon atoms with a mass number greater than 12 are isotopes of carbon. Isotopes are atoms of the same element that have different numbers of neutrons.

Analyze the Choices

Evaluate each answer choice based on the concept of isotopes: A. This option is incorrect because all atoms are carbon atoms, just different isotopes. B. This option is correct because carbon atoms with a mass number greater than 12 are isotopes of carbon. C. This option is incorrect because ions are charged atoms, not atoms with different mass numbers. D. This option is incorrect because the problem mentions 6% of the sample, not 94%. E. This option is incorrect because it doesn't pertain to isotopes or mass numbers.

Choose the Correct Answer

Based on the analysis, the correct conclusion is that 6% of the sample is comprised of carbon isotopes.

Key concepts

Atomic Mass

Atomic mass refers to the mass of an atom, typically expressed in atomic mass units (amu). For carbon, the most common atomic mass is 12 amu, which corresponds to carbon-12. This value represents a weighted average mass of an element's isotopes based on their natural abundance.
The term 'mass number' is used interchangeably with atomic mass, though it specifically refers to the total number of protons and neutrons in an atom's nucleus. Carbon-12, for instance, has 6 protons and 6 neutrons, leading to a mass number of 12.
Understanding atomic mass is crucial because it helps explain why different isotopes of the same element have different physical properties.

• Common atomic masses: For hydrogen, it's about 1 amu; for oxygen, it's about 16 amu.
• Uses: Atomic mass is often used in chemistry to calculate the amounts of substances (stoichiometry).

Carbon Atoms

Carbon atoms are the basic building blocks of carbon-based life forms. Each carbon atom has 6 protons in its nucleus, which defines it as carbon.
The unique electron configuration (2 electrons in the inner shell and 4 in the outer shell) allows carbon to form four covalent bonds with other atoms, making it incredibly versatile in forming various complex compounds.
Carbon atoms can bond with other carbon atoms to form chains, rings, and complex structures. This property is the basis for the vast array of organic molecules, from simple molecules like methane (CH4) to large macromolecules like DNA.

• Versatility: Carbon can form single, double, and even triple bonds.
• Variety: Carbon is found in all known life forms.

Neutrons

Neutrons are subatomic particles found in the nucleus of an atom, except for ordinary hydrogen, where the nucleus contains only a proton. Neutrons have no electric charge and have a mass almost equal to that of protons.
The number of neutrons in an atom's nucleus influences the isotope of the element. For example, carbon-12 has 6 neutrons, while carbon-14 has 8 neutrons.
Neutrons play a critical role in maintaining the stability of the nucleus; too many or too few neutrons can lead to radioactive decay. This property is utilized in various applications, including radiocarbon dating and medical treatments.

• Stability: Balanced neutron-to-proton ratios are crucial for nuclear stability.
• Isotopes: Different numbers of neutrons give rise to different isotopes of an element.

Chemical Elements

Chemical elements are pure substances consisting of only one type of atom, characterized by a specific number of protons in the nucleus. Elements are represented by unique symbols, like C for carbon or O for oxygen.
The periodic table organizes elements according to their atomic number, which is the number of protons in the nucleus. This arrangement helps predict the properties of elements and how they interact with each other.
Various elements combine in specific ways to form all the substances we see around us. For example, water (H2O) is made of hydrogen and oxygen atoms.

• Unique properties: Each element has distinct physical and chemical properties.
• Periodic trends: Elements exhibit trends in properties like electronegativity and atomic radius.
• Combinations: Elements combine to form compounds, like NaCl (table salt) and CO2 (carbon dioxide).