The period.
The 4f subshell is being filled in the lanthanide series of the periodic table, which are also known as the "rare earth elements." They are located in the f-block of the periodic table, filling the 4f subshell from atomic number 58 (Cerium) to 71 (Lutetium).
Exceptions to the general trend of increasing ionization energy across a period in the periodic table occur when there is a half-filled or fully-filled subshell, which results in increased stability and lower ionization energy. This is known as the "half-filled and fully-filled subshell stability" rule.
noble gases.
The actinides family corresponds to the 5f subshell. This subshell can hold a maximum of 14 electrons and is located in the seventh period of the periodic table. The actinides are a series of elements with atomic numbers 89 to 103.
p-block elements have partially filled p-subshell. It is not completely filled.
The 4f subshell is being filled in the lanthanide series of the periodic table, which are also known as the "rare earth elements." They are located in the f-block of the periodic table, filling the 4f subshell from atomic number 58 (Cerium) to 71 (Lutetium).
Exceptions to the general trend of increasing ionization energy across a period in the periodic table occur when there is a half-filled or fully-filled subshell, which results in increased stability and lower ionization energy. This is known as the "half-filled and fully-filled subshell stability" rule.
noble gases.
The actinides family corresponds to the 5f subshell. This subshell can hold a maximum of 14 electrons and is located in the seventh period of the periodic table. The actinides are a series of elements with atomic numbers 89 to 103.
p-block elements have partially filled p-subshell. It is not completely filled.
Chromium is located in the d-block of the periodic table because it has its outermost electrons in the d orbital. Specifically, chromium has the electron configuration [Ar] 3d5 4s1, which places it in the d-block between groups 3 and 4. This electron configuration gives chromium its unique properties and allows it to form various oxidation states.
The periodic table of the elements is filled mostly with metal elements.
It is filled with the names (or chemical symbols) of elements.
The first element in the periodic table with a half-filled orbital is Chromium (Cr), specifically in its electron configuration (1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 3d^5). In the 3d subshell, there are 5 electrons which means it is half-filled (half of the 10 maximum electrons).
The notation "5s² 4d¹⁰ 5p³" represents the electron configuration of an element in the periodic table. It indicates that the element has two electrons in the 5s subshell, ten electrons in the 4d subshell, and three electrons in the 5p subshell. This configuration corresponds to the element Antimony (Sb), which is found in group 15 of the periodic table and has an atomic number of 51.
The exception to the trend of increasing ionization energy across a period in the periodic table occurs when transitioning from group 2 to group 3 elements. This is because the group 3 elements have a slightly lower ionization energy compared to the group 2 elements due to the added stability of having a half-filled or fully-filled subshell.
Leaving spaces and gaps in the periodic table allowed for prediction of new elements and their properties, which were later discovered and filled in. This vindicated the decision to leave gaps, as it demonstrated the power of the periodic table in organizing and predicting the properties of elements.