. 63. The number of electron shells in a magnesium atom is __ A. 1 C. 3 B. 2 D. 4 64. Valence electrons are electrons located __ C. in the outermost energy level A. in the nucleus of an atom D. throughout the atom B. in the first energy level of an atom 65. In an electron dot structure of an element, the dots are used to represent __ A. all the electrons in an atom C. the complete electron arrangement B. the valence electrons D. only the electrons that will participate in bond formation 66. One element that has 5 valence electrons A. lithium C. nitrogen B. carbon D. sulfur 67. Silicon has __ valence electrons. A. 2 C. 6 B. 4 D. 8 68. An atom with 7 valence electrons A. Mn C. I B. N D. Ag 69. Group 17 element with the highest electronegativity is? A. CI C. F B. I D. Br le following has the largest atomic radius? C. Na D. Mg 71. Does ionization energy increase or decrease from left to right across a period on the periodic table? A. increase B. decrease 72. The third element in Group 14 is Germanium. It has an atomic number of 32 What is the atomic number of the second element in this group? A. 14 C. 31 B. 50 D. 33 73. Find the element in period 3, group 15 What is the atomic mass of this element? A. 15 C. 30.97 B. 33 D. 74.92

## Step1<br />For question 63, we need to know the electron configuration of a magnesium atom. The electron configuration of a magnesium atom is \(1s^2 2s^2 2p^6 3s^2\). This shows that shells in a magnesium atom.<br /><br />## Step2<br />For question 64, valence electrons are the electrons in the outermost energy level of an atom. They are the electrons that participate in chemical bonding.<br /><br />## Step3<br />For question 65, in an electron dot structure, the dots represent the valence electrons. These are the electrons in the outermost shell of an atom.<br /><br />## Step4<br />For question 66, nitrogen has 5 valence electrons. This is determined by its electron configuration, which is \(1s^2 2s^2 2p^3\).<br /><br />## Step5<br />For question 67, silicon has 4 valence electrons. This is determined by its electron configuration, which is \(1s^2 2s^2 2p^6 3s^2 3p^6<br />For question 68, iodine (I) has 7 valence electrons. This is determined by its electron configuration, which is \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6 5s^2 4d^{10} 5p^5\).<br /><br />## Step7<br />For question 69, fluorine (F) has the highest electronegativity among the Group 17 elements.<br /><br />## Step8<br />For question 70, sodium (Na) has the largest atomic radius among the given options.<br /><br />## Step9<br />For question 71, ionization energy generally increases from left to right across a period on the periodic table.<br /><br />## Step10<br />For question 72, the atomic number of the14 is 31, which is germanium (Ge).<br /><br />## Step11<br />For question 73, the element in period 3, group 15 is phosphorus (P), and its atomic mass is 30.97.