Question

How many protons electrons and neutrons respectively does 29 CS have

Answer 1

`55 \; \text{e}^(-)`,
`55 \; \text{p}^(+)`, and
`74 \; \text{n}^(0)`- in case cesium-129 is what you were referring to.

Cesium has atomic number
`55` as seen on a modern periodic table. A cesium atom nucleus would thus contain an equal number of protons; in addition to that, a neutral atom of cesium would contain the same number of electrons in its electron cloud.

For a particular isotope,

`\text{Mass number} = \text{Number of protons per nuclei} + \text{Number of Neutrons per nuclei}`.

This isotope of cesium has a mass number of
`129` and contains
`55` protons in each atomic nucleus. One cesium nuclei would therefore contain
`129 - 55 = 74` neutrons.