The modern periodic table consists of 18 groups and 7 periods. What is the atomic number of the element placed in the 4th group and the 4th period?

To find the element in the 4th period and 4th group:The 4th period starts with Potassium ($Z=19$, Group 1) and Calcium ($Z=20$, Group 2).The transition elements start from Group 3 with Scandium ($Z=21$, Group 3).Therefore, the element in Group 4 and Period 4 is Titanium, which has an atomic number ($Z$) of $22$.