Question

New Tab x + entProblemlD=129020404&offset=next 30 of 30 Review Constants Periodic Table In general, electron affinities decrease as you move from left to right across the third period. Explain why this is by completing the statements below. Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. ► View Available Hint(s) Reset Help half-filled completely filled Moving from left to right across across period 3, electrons populate the same shell (35 and 3p subshells). The most stable configuration has valence subshells less partially filled When removing an electron creates a configuration that approaches the most stable electron configuration, the electron affinity will be negative more Submit

Answer 1

6 the Moving from left to right across period. 3, ez same shell. The most stable consigueretion has completely filled subshells. populate the will less neg When removing an e- creates a configueration that approaches the most stable electron confequeration, the electron affinity will be less negative. * The complete etet son configuer ation of my is bes%3B6 28° Whereas the complete eleitscon contiqueration of Al is is 23%2628°38'. & Menoring an e- pross the 3s Orbital of rg requires more energy than removing an es from the 3p orbital of Al. 6 However, when adding an e, the electron affinity for reg is. More negative than that of Al because the election is being added to comply sublevel

Explanation:

1) the most stable electronic configuration is always a completely filled subshell (also called Noble gas configuration if valence shell is np^{​​​​​6} ) because it   becomes very difficult to add or remove an electron to this subshell. So stable configuration order is:

Fully filled Noble gas > fully filled but not Noble gas configuration> half filled subshell configuration> neither fully filled not half filled subshell

2) here the energy will be less negative or may be positive also. Eg in alkali metal (sodium) when we remove one electron, it approaches to most stable configuration I e 1s² 2s² 2p⁶ (Noble gas configuration of Na+) , so adding an electron to sodium will be very difficult. That's why electron affinity of sodium is a positive value.

3) atomic no. Of Mg is 12 and that of Al is 13, so they have above configurations.

4) because in case of mg electron is removed from 3s subshell which is closer to nucleus than 3p subshell of Al. Outer electron of Al is in 3p which is at slighter more distance from nucleus than 3s of Mg. 3p subshell is shielded by 3s orbital, so require less energy than 3s.

5) when we add an extra electron, in case of mg, it comes to empty 3p subshell while in Al, there is already an electron in 3p subshell,so coming electron feel slight repulsion.