Question

identify the period, block, and group in which the elements with the following electron configurations are located. 1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d¹⁰5p⁶6s²4f¹⁴5d¹⁰6p⁶7s²5f¹⁴6d¹⁰7p⁶

o period3_ blockp_ group5_

o period7_ blockp_ group6_

o period7_ blockp_ group8_

o period8_ blocks_ group7_

Explanation:

Step1: Determine the period

The highest - numbered shell with electrons is the period number. Here, the highest shell is the 7th shell (7s and 7p), so the period is 7.

Step2: Determine the block

The block is determined by the sub - shell in which the last electron enters. Since the last electrons enter the p sub - shell (7p), the block is p.

Step3: Determine the group

For p - block elements, the group number is calculated as 12 + the number of electrons in the outermost p sub - shell. Here, there are 6 electrons in the 7p sub - shell, so the group number is 12 + 6=18. But there is an error in the options provided as the correct group for this electron configuration (ending with np6) should be 18. Among the given options, we note the following rules for identification:

• Period: Look at the principal quantum number of the outermost shell.
• Block: s - block (ends with ns1 - 2), p - block (ends with np1 - 6), d - block (ends with (n - 1)d1 - 10ns1 - 2), f - block (ends with (n - 2)f1 - 14(n - 1)d0 - 1ns2).
• Group: For s - block, group number = number of s - electrons; for p - block, group number = 12+ number of p - electrons; for d - block, group number = number of (n - 1)d+ns electrons (with some exceptions).

If we assume a non - noble gas p - block element concept for the given options and consider the general trends, for a p - block element with np6 configuration in period 7, the closest correct option from the given ones in terms of period and block is:

Answer:

Period_7__ Block_p__ Group_8_ (although the correct group for np6 configuration is 18 in the modern periodic table, this is the best fit among the given options)