19. Elements are pure substance because . a. all their atoms have different atomic numbers
b. all their atoms have the same atomic number
c. all their atoms are linked to atoms of other elements
d. everything looks the same
Use the attached sheet of conversion factors to answer the conversion questions.
20. A measurement of 10.70 mm would be converted to cm.
a. 0.00107 c. 107.0
b. 1.070 d. 1070.

answer; i believe that the correct answer is (a) potassium(k)

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.

explanation:

0.07 g/cm³

1.37 g/cm³