Final answer:
When sodium and phosphorus combine, they form sodium phosphide, which is represented by the chemical formula Na3P (option c).
Step-by-step explanation:
When sodium and phosphorus combine, they form sodium phosphide, which is represented by the chemical formula Na3P (option c).
In an electron dot diagram, the symbol for sodium (Na) is surrounded by one dot to represent its one valence electron. Phosphorus (P) is surrounded by five dots to represent its five valence electrons.
When sodium (Na) reacts with phosphorus (P), one sodium atom donates its one valence electron to phosphorus, resulting in the formation of a sodium ion (Na+) and a phosphide ion (P3-). The sodium ion has a stable electron configuration of neon (Na*: 1s²2s²2p6), and the phosphide ion has a stable electron configuration of argon (P³¯: 1s²2s²2p6).
To balance the charges, three sodium ions combine with one phosphide ion, resulting in the formation of Na3P.