Element Orbitals

Why are groups 13 through 18 referred to as the p block on the periodic table?(Look at the ending of the electron configurations you wrote for elements C, Ne, Al, and Cl).

.The p-block elements are unified by the fact that their valence electrons (outermost electrons) are in the p orbital.

How many electrons are needed to fill the first energy level? How many elements are there in the first row of the periodic table?

There are 2 electrons on the first energy level. There are only two elements in the first period: hydrogen and helium.

Look at the electron configurations for O2-and Na+ which you figured out above. Compare them to the other electron configurations you did. Do they have anything in common with one or two of them? Which one(s) and why?

O2 and Be+2 both gained electrons in there outer shell as ions

How many electrons are needed to fill the second energy level(2s+2p)? How many elements are there in the second period of the periodic table?

There are eight electrons needed to fill the second energy level (2 for 2s and 6 for 2p). The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, and neon (8 total).

Using what you now know about electron configurations explain the notion that elements in the same collumn in the periodic table have similar chemical and physical properties.

Those elements in the same column will have the same number of valance electrons and therefore will be able to transfer or share electrons the same way with the same elements.

How do the Aufbau principle work?

The Aufbau principle states that in the ground state of an atom or ion, electrons fill atomic orbitals of the lowest available energy levels before occupying higher levels. For example, the 1s shell is filled before the 2s subshell is occupied. In this way, the electrons of an atom or ion form the most stable electron configuration possible. An example is the configuration 1s2 2s2 2p6 3s2 3p3 for the phosphorus atom, meaning that the 1s subshell has 2 electrons etc.

Why are groups 3 through 12 referred to as the d block on the periodic table? (Look ate the ending of the electron configurations you wrote for element V and Cu).

The d-block elements are unified by mostly having one or more chemically active d-orbital electrons.

Explain what is meant by the Pauli Exclusion Principle

In an atom or molecule, no two electrons can have the same four electronic quantum numbers. As an orbital can contain a maximum of only two electrons, the two electrons must have opposing spins.

Write out the electron configuration of Na+ (Notice that this is an ion)

1s2 2s2 2p6 3s1 (lost 1 electron)

Write out the configuration of O2. Notice that this is an ion.

1s2, 2s2 2p6 (gained 2 electrons)

Something is unusual about the 4s and 3d orbitals. What do you notice about the order in which they are filled?

As 4s orbitals have a lower energy than 3d orbitals, electrons are first filled in the 4s orbital and then in the 3d orbital. This is because the outer shell is maximum shielded from the influence of the nucleus, and therefor lower energy is required to extract electrons from the outermost shell than from an inner shell.

Look at the electron configuration for Neon, a noble gas. Why do you think they are more stable than the other elements?

Becasue they have the maximum number of electrons that their outer shell can hold.

The most stable elements have full outer sub shells. Next most stable are those with half filled shells. Take a look at the electron configuration you wrote for copper. Copper's actual configuration is: 1s2 2s2 2p6 3s2 3p6 4s1 3d10. Give one possible reason for this.

Because they cannot react with any other element by sharing or transfeerring electrons.

Why do you think groups 1 and 2 referred to as the s block of the periodic table? (look at the ending of the electron configurations you wrote for elements K and Be)

Because they have 2 valence electrons they are less reactive than group 1. The s-block elements are unified by the fact that their valence electrons (outermost electrons) are in the s orbital. Most s-block elements are highly reactive metals due to the ease with which their outer s-orbital electrons interact to form compounds.

What is the maximum number of electrons that can be in one orbital or box?

Each orbital can hold two electrons. One spin-up and one spin-down. The S subshell has just one orbital, so can contain 2 electrons max. The P subshell has 3 orbitals, so can contain 6 electrons max. The d subshell has 5 orbitals, so can contain 10 electrons max. The f subshell has l has 7 orbitals so can hold 14 electrons.

What is Hund's rule? That is, How do you go about filling up electron orbitals according this rule?

Every orbital in a sublevel is singly occupied before any orbital is doubly occupied. All of the electrons in singly occupied orbitals have the same spin (to maximize total spin). When assigning electrons to orbitals, an electron first seeks to fill all the orbitals with similar energy (also referred to as degenerate orbitals) before pairing with another electron in a half-filled orbital.

How many electrons are needed to fill the third energy level(3s+3p+3d)? How many elements are there in the third period of the periodic table?

Thus, the third level holds a maximum of 18 electrons: 2 in the s orbital, 6 in the three p orbitals, and 10 in the five d orbitals. The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. The first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block.

What element(s) did you write the configuration for that ended with an electron configuration of 3d? What row or period is it in?

Vandadium which is in row (period) 4 group 5

What element would have the following electron configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d5 (for example: 1s2 means that in the first energy level there are two electrons in an s ordital.)

chromium has the electron configuration od 1s2 2s2 2p6 3s2 3p6 4s2 3d5.