Which of the following is true?
A. Group 1 elements are more reactive than the group 2 elements because they have more valence to lose.
B.Lithium is the least reactive element in group, because its valence electron is held more tightly than the others in the same group.
C. Cesium is the active group metal, because its valence electron is held more tightly than the others in the same group.
D. The least reactive element in group 2 is the one with the largest atomic radium and the least amount of attraction between the nucleus and the valence electrons
To determine which statement is true, we need to understand the trends in reactivity for elements in groups 1 and 2 of the periodic table.
First, let's examine the elements in Group 1, also known as the alkali metals. These elements include lithium (Li), sodium (Na), potassium (K), and so on. Group 1 elements possess one valence electron, which is the outermost electron in their electron configuration.
Statement A suggests that Group 1 elements are more reactive because they have more valence electrons to lose. However, this statement is incorrect. Reactivity is determined by the elements' ability to lose or gain electrons, and having more valence electrons does not necessarily make an element more reactive.
Statement B claims that lithium (Li) is the least reactive element in Group 1 because its valence electron is held more tightly than others in the same group. This statement is also incorrect. In reality, reactivity increases as you go down a group in the periodic table due to weaker electron-nucleus attraction and larger atomic size.
Next, let's look at Group 2, the alkaline earth metals, which include elements such as beryllium (Be), magnesium (Mg), calcium (Ca), and so on. Group 2 elements have two valence electrons in their outermost energy level.
Statement D states that the least reactive element in Group 2 is the one with the largest atomic radius and the least amount of attraction between the nucleus and the valence electrons. This statement is true. As we move down Group 2, the atomic radius increases, and the attraction between the nucleus and the valence electrons decreases. This leads to less reactivity as the valence electrons are held more tightly.
Therefore, the correct answer is D. The least reactive element in Group 2 is the one with the largest atomic radius and the least amount of attraction between the nucleus and the valence electrons.