Question

An atom's Lewis dot structure has three dots. Which of the following elements could it be, and why? Aluminum, because it is in group 13 and has three valence electrons. Lithium, because it is a group 1 element with three total electrons. Magnesium, because it is in period 3 and has three valence electrons. Potassium, because it is an alkali metal and has three inner shell electrons.
Question 2(Multiple Choice Worth 4 points) (03.01 LC) An atom has the following electron configuration. 1s22s22p63s23p3 How many valence electrons does this atom have? 3 5 8 15 Question 3 (Matching Worth 4 points) (03.01 LC) Match each element to the number of electrons in its valence shell. Match Term Definition Chlorine (Cl) A) Eight Neon (Ne) B) Five Phosphorus (P) C) Seven Sulfur (S) D) Six Question 4 (True/False Worth 3 points) (03.01 LC) An atom's valence electrons are located in the atom's outermost energy level. True False Question 5 (Essay Worth 5 points) (03.01 MC) The electron configuration of an element is 1s22s22p63s1. Describe what most likely happens when an atom of this element comes near an atom having seven valence electrons.

Answer 1

Question 1.

The correct statement is " Aluminium, because it is in group 13 and has three valence electrons. The Lewis dot structure for a single atom tells us the number of valence electrons. From the valence electrons we use the periodic table to figure out the identity of the element. Indeed, aluminium has 3 valence electrons and is found in Group 13 on the periodic table.

Question 2.

The correct answer is 5. The outermost shell is called the valence shell and the electrons found in it are called the valence electrons. In this case the outermost shell is n=3, hence all electrons found in this shell are valence electrons. Of course we have the subshells 3s and 3p, but those tells us the region of space where an electron can likely be found but can not explain valence.

Question 3.

Chlorine- 7 valence electrons, Neon- 8 valence electrons, Phosphorus- 5 valence electrons, Sulfur-  6 valence electrons. An element's position in the periodic table helps us figure out it's electron configuration and the group number gives information about the valence electrons.By simply looking at the group number in the periodic table we can know the valence electrons.

Question 4.

The statement is True. As the atomic orbitals get filled the energy levels move further away from the nucleus. The highest orbital that can be occupied by electrons is called the valence shell and the electrons found in it are called the valence electrons. This determine the reactivity of each particular element.

Question 5.

The atom with electron configuration $1s^22s^22p^63s^1$, has an unpaired electron in the 3s orbital which makes it unstable, while the element with 7 valence electrons needs 1 more electron to achieve an octet. Henceforth, the  $1s^22s^22p^63s^1$ loses an electron to the element with 7 electrons to form a bond. The element $1s^22s^22p^63s^1$ becomes positively charged while the element with 7 valence electrons becomes negatively charged, hence we have an ionic bond.

Answer 2

The T/F question is false. Other than that the rest of the answers below are correct. (I just took the test)