Question

an atom of iron has an atomic number of 26 and a mass number of 56. how many protons, neutrons, and electrons are contained in this atom?
26 protons, 56 neutrons, 26 electrons
26 protons, 56 neutrons, 30 electrons
26 protons, 30 neutrons, 26 electrons
26 protons, 30 neutrons, 30 electrons
check answer remaining attempts : 3
activity 2
the atomic number is always the same as the number of neutrons in an element.
is the statement true or false?
true

Explanation:

First Question (Iron Atom Sub - Question)

Step1: Determine the number of protons

The atomic number of an atom is equal to the number of protons. Given that the atomic number of iron is 26, so the number of protons $= 26$.

Step2: Determine the number of neutrons

The mass number of an atom is the sum of the number of protons and neutrons. The formula for the number of neutrons is $n = A - Z$, where $A$ is the mass number and $Z$ is the atomic number. Here, $A = 56$ and $Z = 26$, so the number of neutrons $n=56 - 26=30$.

Step3: Determine the number of electrons

In a neutral atom, the number of electrons is equal to the number of protons. Since the number of protons is 26, the number of electrons $= 26$.

The atomic number of an element is equal to the number of protons (and also the number of electrons in a neutral atom). The number of neutrons is calculated as mass number minus atomic number ($n = A - Z$). For example, in the case of iron, atomic number ($Z = 26$) and number of neutrons ($n = 30$) are not equal. So the statement "The atomic number is always the same as the number of neutrons in an element" is false.

Answer:

26 protons, 30 neutrons, 26 electrons (corresponding to the third option among the given choices)

Second Question (Atomic Number and Neutrons Statement)