An isotope contains 15 protons, 15 electrons, and 17 neutrons. what is the identity of the isotope?

The isotope is phosphorus-32.  

It possesses 15 protons that make it phosphorus, 15 electrons, thus, the charges get balanced, and it is electrically neutral. It has 17 neutrons, so in combination, it has 32 protons/neutrons in the nucleus. Therefore, the name is phosphorus-32.  

The phosphorus-32 is a beta-emitter with a half-life of 14.3 days that is, used regularly in life-science projects, mainly to generate radiolabeled RNA and DNA probes, like for application in Southern Blots and Northern Blots.  

32P

Explanation:

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.