Question

What information cannot be identified if the number of protons for a neutral atom is known?

O number of neutrons
O identity of the element
O atomic number
O number of electrons

Answer 1

The number of protons defines the atomic number and element identity; for a neutral atom, it also equals the number of electrons. The number of neutrons cannot be identified without additional information.

Step-by-step explanation:

If the number of protons for a neutral atom is known, the information that cannot be identified directly is the number of neutrons. The number of protons determines the atomic number (Z), which is definitive of an element's identity. For instance, any atom with six protons is carbon, with an atomic number of 6. In a neutral atom, the number of protons is equal to the number of electrons, hence the atomic number also reveals the number of electrons. The mass number (A) is the total of protons and neutrons in an atom. To find the number of neutrons, you subtract the number of protons (atomic number) from the mass number: A - Z = number of neutrons. However, without the mass number, the number of neutrons cannot be determined just by knowing how many protons are present.