The decrease in size of elements in the lanthanide series with increase in atomic number due to the poor screening power of the 'f' orbital is known as lanthanide contraction. This effect is also found in transition series where it is due to imperfect sheilding of 'd' orbitals.
Lanthanide contraction refers to the gradual decrease in the ionic radii of the lanthanide elements as atomic number increases, due to the increasing effective nuclear charge that pulls electrons closer to the nucleus. Europium is an exception because it has a half-filled f-orbital configuration (4f^7), which provides extra stability and results in a larger ionic radius compared to its neighbors, particularly in the +2 oxidation state. This stability allows Europium to exhibit a distinct electronic structure that deviates from the expected trend of lanthanide contraction.
Because all lanthanide's have almost similar physical as well as chemical properties.
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The lanthanide and actinide series. Trait of lanthanide: Lanthanum, element 57. Trait of actinide: actinium, element 89.
Thulium is an lanthanide element with atomic number 69.
From moving from left to right the atomic size decreases.In case of Lanthanides lanthanide contractions occur and this results from the poor shielding of nuclear charge by 4f electrons,the 6f electrons are drawn towards the nucleus ,thus resulting in smaller atomic radius.
Because all lanthanide's have almost similar physical as well as chemical properties.
its in the Lanthanide series
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No. Americium is an actinide.
Yes, lanthanide and Actinides are transition elements and they are specifically called inner transition elements.
Neodymium is a lanthanide.
57
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The smallest atomic number and atomic weight for a lanthanide is lanthanum itself, element 57. The smallest atomic size is lutecium element 71; the lanthanides steadily decrease in atomic radius through the series, and the smallest is the last of them.
Earth
no !