how many valence electrons are in an atom of gallium (ga), which has the atomic number 31?\n1\n3\n14\n31
how many valence electrons are in an atom of gallium (ga), which has the atomic number 31?\n1\n3\n14\n31
Answer
Explanation:
Step1: Write electron - configuration
Gallium (Ga) with atomic number 31 has the electron - configuration $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{1}$.
Step2: Identify valence electrons
Valence electrons are in the outermost shell. For Ga, the outermost shell is the 4th shell ($n = 4$). The electrons in the 4s and 4p sub - shells of the 4th shell are valence electrons. There are 2 electrons in 4s and 1 electron in 4p, so a total of $2 + 1=3$ valence electrons.
Answer:
B. 3