Valence electrons are those electrons in the outermost...

Valence electrons are those electrons in the outermost principal quantum level (highest $n$ level) of an atom in its ground state. Groups $1 \mathrm{~A}$ to $8 \mathrm{~A}$ have from 1 to 8 valence electrons. For each group of the representative elements (1A-8A), give the number of valence electrons, the general valence electron configuration, a sample element in that group, and the specific valence electron configuration for that element.

Key Concepts

Valence Electrons

Valence electrons are the electrons found in the outermost principal quantum level of an atom. Their arrangement and number are crucial because they determine how atoms interact, bond, and react chemically. Understanding the concept of valence electrons helps in predicting the chemical and physical properties of an element.

Electron Configuration

Electron configuration is the arrangement of electrons within an atom’s orbitals. It describes how electrons occupy different energy levels and sublevels following specific rules like the Pauli exclusion principle and Hund’s rule. This concept is fundamental in explaining the chemical behavior and periodic trends observed across the elements.

Representative Elements

Representative elements, also known as main-group elements, include those in Groups 1A through 8A of the periodic table. These elements display a regular variation in properties as they have valence electrons that follow predictable patterns. Their electron configurations allow for general trends in reactivity and bonding that are key for understanding basic chemical principles.

Periodic Table Groups

Periodic table groups organize elements based on similarities in their valence electron configurations, which in turn lead to analogous chemical properties. Groups 1A to 8A indicate the number of valence electrons present in atoms of those elements, facilitating the prediction of their chemical behavior and participation in bonding and reactions.

Transcript

00:01 So valence electrons, which are the outermost electrons, you can have between 1 to 8 valence electrons for an atom.

00:11 And based upon their group number, you can use that to help determine the number of valance.

00:19 So for groups 1 through 8a, so in other words, looking at our table here, so groups 1, 3, 4, 5, 6.

00:31 Six, seven, and eight a are going to have consecutively one through eight valence electrons.

00:39 And every atom within that group, or element within that group, is going to have that particular number of electrons.

00:47 So for groups, 1a, for all elements that are within 1a, they will have one valence electron.

00:57 2a will have 2 valence electrons, 3a will have 3 valence, 4a, we'll have 4a 5a5, 6a, 6a, 7a, we'll have 7a, and 8a, 8a will have 8.

01:53 One thing with 8a to be aware of is that 8a is going to exclude helium because helium only has two electrons total because it's atomic numbers too so it's only going to have two electrons therefore it cannot have 8 melons electrons so the configuration for each one of these is going to be based upon the number of that it has and also where it is found.

02:27 So this area is where our s orbital is.

02:33 This is our p orbital, this is our d, and then this is our f orbital.

02:43 So based upon where they are, we can use that to figure out what their configuration is.

02:52 So for group 1a, the configuration for the configuration for the valence electron is going to be n, which is the number of the period it is in s -1, because there will be one electron in the s -orbital.

03:06 For group 2, it will again be the number of the period, s -2.

03:12 3 will be n -s -2, so meaning the s -orbital is full, and then it'll be n -p -1.

03:21 Again, n is depending upon the period, is n...

Please give Ace some feedback