A 0.4272 g sample of an element contains 2.241 x 10 ^21 atoms . what is the symbol of the element?

Likely (indium.)

Explanation:

Number of atoms: .

Dividing, , the number of atoms by the Avogadro constant, , would give the number of moles of atoms in this sample:

.

The mass of that many atom is . Estimate the average mass of one mole of atoms in this sample:

.

The average mass of one mole of atoms of an element ( in this example) is numerically equal to the average atomic mass of that element. Refer to a modern periodic table and look for the element with average atomic mass . Indium, , is the closest match.

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.