Final answer:
The compound formed between sodium and phosphorus is likely to be sodium phosphide (Na3P), where three sodium atoms each give one electron to one phosphorus atom, resulting in a compound with a 1:1 ratio of Na+ to P3− ions.
Step-by-step explanation:
The student asked for the chemical formula of the compound formed between sodium and phosphorus. When considering compounds such as sodium chloride (NaCl) and phosphorus trichloride (PCl3), we can deduce that sodium (Na) loses one electron to form a cation (Na+ ), while chlorine (Cl) and phosphorus (P) gain electrons to form anions (Cl−) and share electrons to complete their octets respectively.
Phosphorus typically forms covalent bonds, as seen in PCl3. But when reacting with sodium, a metal, phosphorus is likely to form an ionic compound. Phosphorus can form different ionic compounds with sodium depending on the reaction conditions, but sodium phosphide (Na3P) is one of the known binary ionic compounds formed when three sodium atoms transfer one electron each to one phosphorus atom. This results in a 1:1 ratio of Na+ to P3− ions in the final compound, Na3P.