To determine the atomic number of a neutral atom that has 5 neutrons and 4 electrons, let's break down the problem step by step.
1. Understanding Atomic Number:
- The atomic number of an atom is defined as the number of protons in the nucleus of the atom.
- In a neutral atom, the number of protons is equal to the number of electrons. This is because the positive charge of the protons and the negative charge of the electrons balance each other out, resulting in no overall charge.
2. Given Information:
- The atom is neutral, meaning the number of protons equals the number of electrons.
- The atom has 4 electrons.
3. Relating Electrons to Protons:
- Since the atom is neutral and it has 4 electrons, it must also have 4 protons.
4. Finding the Atomic Number:
- The atomic number is equal to the number of protons in the nucleus.
- Therefore, if the atom has 4 protons, its atomic number is 4.
Thus, the atomic number of the atom with 5 neutrons and 4 electrons is [tex]\( \boxed{4} \)[/tex].
The correct answer is:
b) 4
