Lewis Dot Structure Covalent Bonds Calculator Formula
Lewis Dot Structure Covalent Bonds
Lewis Structure Covalent Compound Calculator
Lewis Dot Structure Covalent Bonds Calculator Worksheet

Molecular Cations and Anions

Molecules can also lose or gain electrons to become cations or anions. For example, the NO₃ molecule will gain an electron to form the nitrate anion.

Chemistry Worksheet Lewis Dot Structures Name: Block. Draw Lewis structures for the following covalent compounds: Created Date: 3/28/2014 11:29:01 AM. Here is the simple view on this important topic: In Lewis structures, we show each covalent bond as two dots which represent a pair of electrons. For example: Therefore, we can say that Lewis structures are electron dot representations for molecules. The trick here is to keep track of the electrons and correctly place the atoms in the molecule.

If you count up all of the electrons you'll find that all of the atoms feel like neon.

Here is the ammonium ion, an example of a molecular cation.

The ammonium ion has given up an electron to become a cation.

Ionic Bonds

Ionic bonds are generally formed when you bring atoms which really want to lose electrons together with atoms which really want to gain electrons.

The Na⁺ cation and the Cl^- anion are held together by electrostatic or ionic bonds. There is no sharing in ionic bonding. The anion takes the electron for itself and the cation is happy to get rid of its electron. The ions in ionic compounds are arranged in three-dimensional structures. There are no discrete molecules of NaCl. We can only write an empirical formula of NaCl.

Here are some other examples.

NH₄Cl :	here NH₄⁺	= cation
here Cl^-	= anion
BaCl₂ :	here Ba²⁺	= cation
here Cl^-	= anion

All substances are electrically neutral. We can use this fact to obtain the chemical formula of an ionic compound.

Ba²⁺	and	SO₄^2-	form	BaSO₄
Na⁺	and	S^2-	form	Na₂S

Notice that in Na₂S, two sodium cations were needed to balance the -2 charge of S^2-, making things electrically neutral.

Homework from Chemisty, The Central Science, 10th Ed.

2.39, 2.41, 2.43, 2.45, 2.53, 2.55

Learning Objectives

Define covalent bond.
Illustrate covalent bond formation with Lewis electron dot diagrams.

Ionic bonding typically occurs when it is easy for one atom to lose one or more electrons, and for another atom to gain one or more electrons. However, some atoms will not give up or gain electrons easily. Yet they still participate in compound formation. How? There is another mechanism for obtaining a complete valence shell: sharing electrons. When electrons are shared between two atoms, they form a covalent bond.

Let us illustrate a covalent bond by using H atoms, with the understanding that H atoms need only two electrons to fill the 1s subshell. Each H atom starts with a single electron in its valence shell:

[mathbf{H, cdot }; ; ; ; ; mathbf{cdot : H}nonumber ]

The two H atoms can share their electrons:

[mathbf{H}: mathbf{: H}nonumber ]

We can use circles to show that each H atom has two electrons around the nucleus, completely filling each atom's valence shell:

Because each H atom has a filled valence shell, this bond is stable, and we have made a diatomic hydrogen molecule. (This explains why hydrogen is one of the diatomic elements.) For simplicity's sake, it is not unusual to represent the covalent bond with a dash, instead of with two dots:

H–H

Because two atoms are sharing one pair of electrons, this covalent bond is called a single bond. As another example, consider fluorine. F atoms have seven electrons in their valence shell:

These two atoms can do the same thing that the H atoms did; they share their unpaired electrons to make a covalent bond.

Note that each F atom has a complete octet around it now:

We can also write this using a dash to represent the shared electron pair:

There are two different types of electrons in the fluorine diatomic molecule. The bonding electron pair makes the covalent bond. Each F atom has three other pairs of electrons that do not participate in the bonding; they are called lone pair electrons. Each F atom has one bonding pair and three lone pairs of electrons.

Covalent bonds can be made between different elements as well. One example is HF. Each atom starts out with an odd number of electrons in its valence shell:

Killing floor - steampunk character pack 2 download free. The two atoms can share their unpaired electrons to make a covalent bond:

Note that the H atom has a full valence shell with two electrons, while the F atom has a complete octet of electrons.

Example (PageIndex{1}):

Use Lewis electron dot diagrams to illustrate the covalent bond formation in HBr.

Solution

Lewis Dot Structure Covalent Bonds Calculator

HBr is very similar to HF, except that it has Br instead of F. The atoms are as follows:

The two atoms can share their unpaired electron:

Exercise (PageIndex{1})

Use Lewis electron dot diagrams to illustrate the covalent bond formation in Cl₂.

Answer

More than two atoms can participate in covalent bonding, although any given covalent bond will be between two atoms only. Consider H and O atoms:

The H and O atoms can share an electron to form a covalent bond:

The H atom has a complete valence shell. However, the O atom has only seven electrons around it, which is not a complete octet. This can be fixed by including a second H atom, whose single electron will make a second covalent bond with the O atom:

(It does not matter what side the second H atom is positioned on.) Now the O atom has a complete octet around it, and each H atom has two electrons, filling its valence shell. This is how a water molecule, H₂O, is made.

Example (PageIndex{2}):

Use a Lewis electron dot diagram to show the covalent bonding in NH₃.

Solution

The N atom has the following Lewis electron dot diagram:

It has three unpaired electrons, each of which can make a covalent bond by sharing electrons with an H atom. The electron dot diagram of NH₃ is as follows:

Lewis Dot Structure Covalent Bonds Calculator Formula

Exercise (PageIndex{2})

Use a Lewis electron dot diagram to show the covalent bonding in PCl₃.

Answer

There is a simple set of steps for determining the Lewis electron dot diagram of a simple molecule. First, you must identify the central atom and the surrounding atoms. The central atom is the atom in the center of the molecule, while the surrounding atoms are the atoms making bonds to the central atom. The central atom is usually written first in the formula of the compound (H₂O is the notable exception). After the central and surrounding atoms have been identified, follow these steps:

Count the total number of valence electrons. Add extra if the species has negative charges and remove some for every positive charge on the sp