Question

Some isotopes of elements are unstable and decay into other, more stable isotopes over time. for example, it takes 153 years for half of a sample of silicon (si) atoms with 14 protons, 14 electrons, and 18 neutrons to decay. what is the name of this specific silicon isotope.
a. silicon-14
b. silicon-32
c. silicon-46
d. silicon-153

Answer 1

The correct answer is option a, silicon-14

Number of electrons = 14

Number of protons = 14

Number of neutrons = 18

Since atomic number is equal to the number of protons, the atomic number of this specific silicon isotope is 14.

Also, mass number is equal to number of protons and number of neutrons. So mass number so this specific silicon isotope is 14 + 18 = 32

The name of this specific silicon isotope is silicon-14.

Silicon-14 is represented as ³²Si₁₄