In a transition series, as the atomic number increases, paramagnetism

In a transition series, with the increase in atomic number, the paramagnetism

The atomic radii of transition elements decreases slowly as the atomic number increases in a period. Account for it

In the transition series, with an increase in atomic number, the atomic radius does not change very much. Why is it so?

Explain the following observation : In general, the atomic radii of transition elements decrease with atomic number in a given series.