Question

1. Which of the following is true of electron shells?

a. a shell is an energy level of electrons at a characteristic average distance from the nucleus of the atom

b. a shell is the 3D space where an electron is found 90% of the time

c. all electron shells can hold the same number of electrons

d. the electrons in the first shell have more potential energy than the electrons in the valence shell

2.  ¹⁴C is a radioactive isotope of carbon (atomic number 6). How many electrons are in the valence shell of ¹⁴C?

a. 4

b. 6

c. 8

d. 14

e. none thats why its radioactive

3. How many single covalent bonds can carbon form w other atoms?

a. 2

b. 3

c. 4

d. 5

e. 6

Answer 1

Ans-1- a shell or a principle energy level is the orbit followed by the electrons with different energy level around the nucleus. Each shell has definite number of electrons. Potential energy of the last shell, that is valance shell is maximum.

So option A is correct answer.

Ans-2- main difference between C 14 and C 12 is that C 14 has 8 neutron while C 12 has only 6 electron. Like other element of group 14 carbon also have 4 valance electrons. So the number of electrons in balance shell is 4.

Ans-3- since there are 4 electrons in valance shell carbon can form 4 single covalent bonds with other atoms.