Which elements are most likely to react in the same manner in a chemical reaction?

• A. Elements with the same atomic mass
• B. Elements with the same number of valence electrons
• C. Elements with the same number of neutrons
• D. Elements located in the same period of the periodic table

Answer: (B)

Verified step by step guidance

1. Understand that chemical reactivity is primarily determined by the arrangement of electrons, especially the valence electrons, which are the outermost electrons involved in bonding.
2. Recall that elements with the same number of valence electrons tend to have similar chemical properties because they form similar types of bonds and react in comparable ways.
3. Recognize that atomic mass and number of neutrons do not directly influence chemical reactivity, as these relate more to the nucleus and isotopes rather than electron behavior.
4. Note that elements in the same period (horizontal row) have the same number of electron shells but different numbers of valence electrons, so their chemical behavior can vary significantly.
5. Conclude that the best predictor for similar chemical reactions among elements is having the same number of valence electrons, which is why elements in the same group (vertical column) of the periodic table behave similarly.