"Though size increases rapidly from N to P of group 15th elements but from As to Bi there is small rise in the size of the elements." Com-ment.

Mention the general characteristics of groups 15 elements with reference to their atomic size.

The short from electronic configurtion of two elements are [Ar] 4s^1 and [Ne]3p^5 . Identify the two elements.

What are the causes for which lithium shows some anomalous properties from the other elements in the group I.

An object is placed 30cm away from a concave lens of focal length 15cm. Find the position, size and nature of the image.

The bQB A of a pendulum released from 30° to the vertical hits another bQB B of the same mass at rest on a table as shown in Fig. 6.15. How high does the bQB A rise after the collision? Neglect the size of the bQBs and assume the collision to be elastic.

"In a given series of the transition elements the atomic size increases but this variation in size is very small". Explain.

An object of 4 cm height is placed in front of a concave lens. An image of size 2 cm is formed at a distance of 15 an from the lens. Find the object distance and the focal length of the lens.