Are coinage metals and zinc transition elements?

Copper is in, zinc is out

1. Electronic configurations and oxidation states

Are coinage metals and zinc transition elements?

2. Two complete 3d sublevels

Copper (

[Ar]\ 4s¹\ 3d¹⁰

) and zinc (

[Ar]\ 4s²\ 3d¹⁰

) both have a complete 3d in the atom.

Pick the right answer

Predict: which of them are transition elements?

A. Both: they are in the d-block
B. Neither: their atoms are $d¹⁰ d^{10}$
C. Copper only
D. Zinc only

الشرح

Both atoms have a complete 3d. In

Cu²⁺ Cu X^{2 +}

the 3d becomes incomplete (

3d⁹ 3 d^{9}

), so copper is a transition element; in

Zn²⁺ Zn X^{2 +}

the 3d stays complete (

3d¹⁰ 3 d^{10}

), so zinc is not.

3. Strip copper

Copper's oxidation states are +1 and +2. Remove electrons and watch 3d.

electrons lost 0

↑

↑↓↑↓↑↓↑↓↑↓

Cu atom:

[Ar]\ 4s¹\ 3d¹⁰

: d complete

4. Coinage metals

Coinage metals

Copper, silver and gold, in group IB.

Metal	Atom
$₂₉Cu X_{29} X_{229}^{2} Cu$	$4s¹\ 3d¹⁰$
$₄₇Ag X_{47} X_{247}^{2} Ag$	$5s¹\ 4d¹⁰$
$₇₉Au X_{79} X_{279}^{2} Au$	$6s¹\ 5d¹⁰$

Book Exercise 1, p.10

In the atom, the d sublevel is completely filled (

d¹⁰ d^{10}

) in all three.

But in the oxidation state +2 or +3, d is partially filled (

d⁹ d^{9}

d⁸ d^{8}

). So they are transition elements.

5. Strip zinc

Zinc's only oxidation state is +2. Remove its electrons and watch 3d.

electrons lost 0

↑↓

↑↓↑↓↑↓↑↓↑↓

Zn atom:

[Ar]\ 4s²\ 3d¹⁰

6. Worked: gold; your turn: silver

Step 1: The gold atom

↑

↑↓↑↓↑↓↑↓↑↓

₇₉Au X_{79} X_{279}^{2} Au

: …

6s¹\ 5d¹⁰

: d complete

Step 2: Gold in the +3 state

↑↓↑↓↑↓↑↑

Au³⁺ Au X^{3 +}

: …

5d⁸ 5 d^{8}

: d incomplete

Gold loses its 6s electron, then two 5d electrons.

5d⁸ 5 d^{8}

is incomplete, so gold is a transition element.

Your turn: silver in the +2 state

[Kr] stands for krypton's 36 electrons, as [Ar] stands for argon's 18.

Fill in the blanks

₄₇Ag X_{47} X_{247}^{2} Ag

: [Kr]

5s¹\ 4d¹⁰

Ag²⁺ Ag X^{2 +}

: [Kr] 4d_____ . So silver _____ a transition element (type: is / is not).

الشرح

Ag²⁺ Ag X^{2 +}

: [Kr]

4d⁹ 4 d^{9}

: incomplete. So silver is a transition element.

Need a hint?

The outer s electron leaves first.
A 2+ ion has lost two electrons in total.
Is $4d¹⁰ 4 d^{10}$ minus one complete?

7. New cases

Pick the right answer

Element X: atom [Kr]

4d¹⁰ 4 d^{10}

. In its +2 state: [Kr]

4d⁸ 4 d^{8}

. Is X a transition element?

A. Yes: d is incomplete in its +2 state
B. No: its atom is $d¹⁰ d^{10}$
C. No: it has no s electrons in the atom

الشرح

The atom of X is

4d¹⁰ 4 d^{10}

, but in the +2 state it is

4d⁸ 4 d^{8}

, an incomplete d sublevel, so X is a transition element (X is palladium).

True or false?

Groups IB and IIB are both outside the transition elements.

الشرح

Cu, Ag, Au have

d⁹ d^{9}

d⁸ d^{8}

in the +2 or +3 state. Zn, Cd, Hg stay

d¹⁰ d^{10}

8. Summary

Coinage metals (Cu, Ag, Au): $d¹⁰ d^{10}$ in the atom, but $d⁹ d^{9}$ or $d⁸ d^{8}$ in the +2 or +3 state. They are transition elements.
Zn, Cd, Hg: $d¹⁰ d^{10}$ in the atom and in the +2 ion. They are not transition elements, though they sit in the d-block.
Test the atom first, then its oxidation states.

Element	Atom	Ion	d in the ion	Transition element?
$₂₉Cu X_{29} X_{229}^{2} Cu$	$[Ar]\ 4s¹\ 3d¹⁰$	$Cu²⁺ Cu X^{2 +}$ : $[Ar]\ 3d⁹$	incomplete	yes
$₃₀Zn X_{30} X_{230}^{2} Zn$	$[Ar]\ 4s²\ 3d¹⁰$	$Zn²⁺ Zn X^{2 +}$ : $[Ar]\ 3d¹⁰$	complete	no

Test the atom, then the ion

Back to the hook: can you explain why copper is a transition element but zinc is not?

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