Isotope Calculations in Chemistry

The video tutorial explains isotopes, focusing on chlorine and lithium. It describes isotopes as elements with the same number of protons but different numbers of neutrons. The tutorial calculates the number of neutrons in chlorine isotopes (chlorine-35 and chlorine-37) and lithium isotopes (Li-6 and Li-7) using the formula: neutrons = mass number - protons. Chlorine has an atomic number of 17, leading to 18 neutrons in chlorine-35 and 20 in chlorine-37. Lithium, with an atomic number of 3, has isotopes with 3 and 4 neutrons, resulting in mass numbers of 6 and 7, respectively.

What do isotopes of an element have in common?

• Same number of neutrons

• Same number of protons

• Same number of electrons

• Same mass number

How many protons does chlorine have?

• 18

• 20

• 17

• 35

What is the mass number of chlorine-35?

• 18

• 37

• 35

• 17

How many neutrons are in chlorine-37?

• 18

• 17

• 37

• 20

What is the atomic number of lithium?

• 7

• 6

• 4

• 3

How many stable isotopic forms does lithium have?

• Two

• One

• Four

• Three

How many neutrons does the isotope Li-6 have?

• 7

• 6

• 4

• 3

What is the mass number of Li-7?

• 7

• 4

• 6

• 3

How do you calculate the mass number of an isotope?

• Number of protons plus number of neutrons

• Number of protons minus number of neutrons

• Number of neutrons minus number of protons

• Number of electrons plus number of neutrons