Writing Electron Configurations Noble gas method Write an

Writing Electron Configurations Noble gas method

Write an electron configuration for uranium (92 electrons).

Write an electron configuration for uranium (92 electrons). • 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 p 66 s 24 f 145 d 106 p 67 s 25 f 4

Write an electron configuration for uranium (92 electrons). • 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 p 66 s 24 f 145 d 106 p 67 s 25 f 4 • This can take a long time for large atoms, especially when the valence electrons are the only ones we care about.

Noble gas method • This method represents a much quicker and easier way to identify valence electrons.

Noble gas method • This method represents a much quicker and easier way to identify valence electrons. • The s-sublevel is always the first sublevel to be filled within a particular energy level.

Noble gas method • This method represents a much quicker and easier way to identify valence electrons. • The s-sublevel is always the first sublevel to be filled within a particular energy level. • The outermost energy level is the most important, so why not start there?

Noble gas method • This method represents a much quicker and easier way to identify valence electrons. • The s-sublevel is always the first sublevel to be filled within a particular energy level. • The outermost energy level is the most important, so why not start there? • 7 s 25 f 4 (start with the 7 th energy level)

Noble gas method • This method represents a much quicker and easier way to identify valence electrons. • The s-sublevel is always the first sublevel to be filled within a particular energy level. • The outermost energy level is the most important, so why not start there? • 7 s 25 f 4 (start with the 7 th energy level) • [Rn] is used to represent the first 86 electrons.

• [Rn] means the same thing as 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 p 66 s 24 f 145 d 106 p 6

• [Rn] means the same thing as 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 p 66 s 24 f 145 d 10 • Therefore, [Rn]7 s 25 f 4 means the same thing as 1 s 22 p 63 s 23 p 64 s 23 d 104 p 65 s 24 d 105 p 66 s 24 f 145 d 106 p 67 s 25 f 4

Write an electron configuration for selenium using the noble gas method.

Write an electron configuration for selenium using the noble gas method. • Start with the s-sublevel for the period selenium is in (4 s)

Write an electron configuration for selenium using the noble gas method. • Start with the s-sublevel for the period selenium is in (4 s) • Select the noble gas from the previous period and place it in brackets ([Ar]4 s)

Write an electron configuration for selenium using the noble gas method. • Start with the s-sublevel for the period selenium is in (4 s) • Select the noble gas from the previous period and place it in brackets ([Ar]4 s) • The argon accounts for 18 of the 34 electrons needed. Continue until you reach 34.

Write an electron configuration for selenium using the noble gas method. • Start with the s-sublevel for the period selenium is in (4 s) • Select the noble gas from the previous period and place it in brackets ([Ar]4 s) • The argon accounts for 18 of the 34 electrons needed. Continue until you reach 34. • [Ar]4 s 23 d 104 p 4

Electron configuration exceptions

Electron configuration exceptions • Electrons are arranged in a way that maximizes stability.

Electron configuration exceptions • Electrons are arranged in a way that maximizes stability. • Sublevels that are filled are the most stable. Half-filled sublevels are stable. Anything else is unstable.

Chromium • The noble gas configuration for chromium is expected to be [Ar]4 s 23 d 4

Chromium • The noble gas configuration for chromium is expected to be [Ar]4 s 23 d 4 The 3 d sublevel is unstable due to the single empty orbital.

Chromium • The noble gas configuration for chromium is expected to be [Ar]4 s 23 d 4 Promoting one of the 4 s electrons increases stability.