20. Which of the following statements regarding subshell filling order for a neutral atom is/are CORRECT? 1. Electrons are assig
ned to the 4f subshell before they are assigned to the 6s subshell. 2. Electrons are assigned to the 5d subshell before they are assigned to the 6p subshell. 3. Electrons are assigned to the 4p subshell before they are assigned to the 4s subshell. a. 1 only b. 2 only c. 3 only d. 1 and 3 e. 1, 2, and 3
Electrons are filled in atoms according to the Aufbau principle. Electrons are filled into lower energy orbital before the filling of higher energy orbitals and this sequence must be followed in filling electron orbitals.
The order of arrangement of energy levels may be shown as follows; 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p. This implies that 4f>6s, hence 6s is filled before 4f.
Also, the 6p level > 5d level hence this is the correct option. You must fill the 5d level before you feel the 6p level.
Calculating for the moles of H+ 1.0 L x (1.00 mole / 1 L ) = 1 mole H+
From the given balanced equation, we can use the stoichiometric ratio to solve for the moles of PbCO3: 1 mole H+ x (1 mole PbCO3 / 2 moles H+) = 0.5 moles PbCO3
Converting the moles of PbCO3 to grams using the molecular weight of PbCO3 0.5 moles PbCO3 x (267 g PbCO3 / 1 mole PbCO3) = 84.5 g PbCO3
