in a periodic table the penultimate shell of which of the element in incomplete
Answers
Penultimate” means “next to last”. The ultimate shell would be the highest-numbered occupied shell for a given atom, and the penultimate shell is the second-highest occupied shell. In the d-block elements, the d orbitals of the penultimate shell are being filled as you move across the block from left to right. For instance, in the 4th row, K has one electron in the 4s orbital and its 3d orbitals are empty. Ca has 2 electrons in the 4s orbital. Sc has 2 electrons in the 4s orbital and one in the 3d orbital. As you move further, electrons are added to the 3d orbital until it is completely filled with 10 electrons in Zn.
Answer:
In the periodic table the penultimate shell is found to be incomplete in transition metals.
Explanation:
As we know that when we move from one element to next element in the periodic table the electrons get filled in the outermost shell. But in the case of transition metals for example 3d-transition metals, outermost 4s-orbital has already two electrons means it is completely filled. so the electrons entered in 3d- orbital which is penultimate shell in case of 3d-transition metals. In 4th period when we move from left to right the 3d transition metals have incomplete 3d- orbital i.e. penultimate shell.