How many valence electrons are in an atom with the electron configuration in example a? example a: 1s22s22p63s23p4 6 4 2 18

6.

Explanation:

Valence electron may be defined as the electrons present in the outermost shell. The valence electron has the ability to lose or gain the other electron and also determines the chemical property of the element.

The outermost electrons can be calculated by looking at the outermost shell. In the given example 1s22s22p63s23p4, the number of valence electrons are 6 ( the sum of electron present in the 3s and 3p orbitals.

Thus, the correct answer is option (1).

i think that d. wind is the answer.   i missed the question when i answered a. currents.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.