The element with Ar4s2 3d9 electron configuration is cobalt (Co).
The noble gas notation for the copper(II) ion (Cu2+) is [Ar]3d9. This notation represents the electronic configuration of copper when all inner shell electrons up to argon are included before the outer d orbital configuration of 3d9.
The abbrieviated electron configuration of copper is [Ar] 4s23d9
The element in question has an atomic number that is 2 less than element C and its electron configuration ends in 3d9. This would suggest that the element is one of the transition metals that comes before element C in the periodic table. A possible candidate fitting this description is manganese (Mn), which has an atomic number of 25 and an electron configuration of [Ar] 3d5 4s2.
Copper has a partially filled d orbital to achieve greater stability. Hence, it gives up one electron from the 4s orbital to make the 3d orbital completely filled with 10 electrons, which is a more stable configuration. This results in the electron configuration of 3d10 4s1 for copper rather than 3d9 4s2.
The electron configuration of copper(II) is [Ar] 3d9 . Copper is [Ar] 3d10 4s1
The electronic configuration od Cu is [Ar] 3d10 4s1 This is an exception to the aufbau principle which would predict [Ar] 3d9 4s2.
Cobalt has 9 valence electrons and generally cant lose 9 electrons to achieve the noble gas configuration.
Cu has an anomalous electron configuration. Cu = 1s2 2s2 2p6 3s2 3p6 4s1 3d10, it does not follow the usual pattern. In this case, the 3d subshell is filled before the 4s, which usually happens in the reverse order (1s2 2s2 2p6 3s2 3p6 4s2 3d9).
The number of electrons in a subshell of a copper atom depends on which subshell you are referring to. Copper has 29 electrons, so its electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d9. The 3d subshell in copper contains 9 electrons.
The electron configuration of a Copper(II)ion is [Ar]4s0 3d9.
Trigonal pyramidal - don't forget nitrogen's lone pair.