## Chemistry: The Central Science (13th Edition)

The electron configuration of titanium is $$1s^22s^22p^63s^23p^64s^23d^2$$ A titanium atom has 2 valence electrons.
1) Find out the number of electrons in a titanium atom The atomic number of titanium is 22. That means there are 22 electrons in a titanium atom. 2) Arrange the electrons into the shells and subshells in order of increasing levels of energy - The first 2 electrons occupy the lowest level subshell $1s$. - The next 2 electrons occupy the next lowest level subshell $2s$. - The next 6 electrons occupy the next lowest level subshell $2p$. - Moving on, the next 2 electrons occupy subshell $3s$. - The next 6 electrons occupy subshell $3p$. - The next 2 electrons occupy the next lowest level subshell $4s$. - The last 2 electrons occupy the next lowest level subshell $3d$. Therefore, the electron configuration of titanium is $$1s^22s^22p^63s^23p^64s^23d^2$$ We are told that the valence electrons, in most cases, are those in the outermost occupied shell. Here $n=4$, the outermost shell, has 2 electrons in subshell $4s$. Therefore, a titanium atom has 2 valence electrons.