What are the 4 types of orbitals and how many electrons can each type hold

The s subshell is a spherical orbital which can contain up to two electrons. Each energy level has one s subshell.The p subshell has three dumbbell-shaped orbitals, arranged at right angles to each other. Each of these orbitals can contain up to two electrons, so a fully-filled p subshell will contain six electrons. The p subshell can be found in energy levels of two or higher.The d subshell has a set of five orbitals, arranged to lie along the x, y, and z planes. (The picture above really helps here.) Each of the five orbitals can contain up to two electrons, so a fully loaded d subshell will contain ten electrons. This subshell can be found in energy levels of three or higher.The f subshell has a set of seven orbitals, symmetrically distributed throughout the x, y, and z planes. Each of the seven orbitals can contain up to two electrons, for a total of fourteen electrons in a fully-stacked shell. This subshell can be found in energy levels of four or higher. Electrons are filled into these orbitals, up to two per orbital, starting from the lowest shell.

http://college-cram.com/study/chemistry/atoms-and-molecules/electron-orbitals/

Answer : option a) 84explanation :

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.

The answer is d- principle of faunal succession.