Bromine (Br) is atomic number 35. How many protons, neutrons, and electrons in a negative ion of Bromine-79 (Br” -79)?
A 35p. 44n, 35e
B 35p, 44n, 36e
C 35p, 79, 36e.
D 79p, 35, 36e
The correct answer and explanation is :
The correct answer is B: 35p, 44n, 36e.
Explanation:
Bromine (Br) has an atomic number of 35, which means that every neutral atom of bromine contains 35 protons and 35 electrons. The atomic number defines the number of protons in an atom.
Now, let’s look at the specifics for the given isotope Bromine-79 (Br-79):
- Protons:
- The atomic number of Bromine is 35, so there are 35 protons in the nucleus of any bromine atom, whether it is a neutral atom or an ion.
- Neutrons:
- The mass number of Bromine-79 is 79 (denoted as Br-79). The mass number is the sum of protons and neutrons in the nucleus of an atom.
- To calculate the number of neutrons, we subtract the number of protons from the mass number:
[
\text{Neutrons} = \text{Mass number} – \text{Protons} = 79 – 35 = 44
]
So, there are 44 neutrons in the nucleus of a Bromine-79 atom.
- Electrons in a Negative Ion (Br⁻):
- Bromine-79 in its negative ion form (Br⁻) has gained an extra electron compared to a neutral bromine atom. A neutral bromine atom has 35 electrons (equal to the number of protons). However, in a negative ion (Br⁻), one additional electron is gained, making the total number of electrons 36.
Thus, for the negative ion of Bromine-79, the composition is:
- 35 protons,
- 44 neutrons,
- 36 electrons.
This corresponds to option B: 35p, 44n, 36e.
Image (diagram of the atom):
Simple diagram of a Bromine-79 ion (Br⁻) with 35 protons, 44 neutrons, and 36 electrons.
Here is a diagram illustrating the structure of a Bromine-79 negative ion (Br⁻) with 35 protons, 44 neutrons, and 36 electrons.