How to draw BeH2 Lewis Structure? - Science Education and Tutorials

Drawing BeH2 Lewis Structure is very easy. Here in this post, we described step by step method to construct BeH2 Lewis Structure.

Table of Contents

Key Points To Consider When Drawing The BeH2 Lewis Structure

A three-step approach for drawing the BeH2 Lewis structure can be used. The first step is to sketch the Lewis structure of the BeH2 molecule, to add valence electron around the Beryllium atom; the second step is to valence electron to the two hydrogen atoms, and the final step is to combine the step1 and step2 to get the BeH2 Lewis Structure.

The BeH2 Lewis structure is a diagram that illustrates the number of valence electrons and bond electron pairs in the BeH2 molecule. The geometry of the BeH2 molecule can then be predicted using the Valence Shell Electron Pair Repulsion Theory (VSEPR Theory), which states that molecules will choose a BeH2 geometrical shape in which the electrons have from one another.

Finally, you must add their bond polarities to compute the strength of the Be-H bond (dipole moment properties of the BeH2 molecule). The Beryllium-hydrogen bonds in beryllium hydride(BeH2), for example, are polarised toward the more electronegative hydrogen, and because both bonds have the same size and opposite to each other, their sum is zero due to the BeH2 molecule’s bond dipole moment, and the BeH2 molecule is classified as a nonpolar molecule.

The molecule of beryllium hydride (with linear geometry) is tilted at 180 degrees and has a difference in electronegativity values between hydrogen and beryllium atoms, with beryllium’s pull being less than hydrogen’s terminal in the BeH2 molecule. As a result, it has no dipole moment. The BeH2 molecule has no dipole moment due to an equal charge distribution of negative and positive charges.

BeH2 Lewis Structure:

The central atom is beryllium, which is bordered on two terminals with hydrogen atoms. Beryllium has two outermost valence electrons, indicating that it possesses two electrons in its outermost shell, whereas hydrogen only has one valence electron in its outermost shell. To complete the octet of the hydrogen atom, a hydrogen terminal atom requires one electron. If you’re interested in learning more about the hydrogen octet rule, please see in our previous post.

Two hydrogen atoms establish covalent connections with the beryllium atom as a result, leaving the beryllium atom without any lone pairs. There are no lone pairs on the beryllium central atom that resist the bond pairs of the two Be-H. According to VSEPR theory, no electronic repulsion leads the BeH2 molecule to take on a linear molecular shape like NO2+ and CS2.

The BeH2 molecule’s Be-H bonds are arranged in a symmetrical order around the linear geometry, giving rise to the linear BeH2 shape. The BeH2 molecule has a linear molecular geometry because there is no electrical repulsion between them.

Electronegative Difference Calculation BeH2 Molecule:

Beryllium has an electronegativity of 1.57, while hydrogen has an electronegativity of 3.16 in the BeH2 molecule. The difference in electronegativity can be estimated using the method below.

The electronegative value difference between beryllium and hydrogen
Electronegativity value of beryllium = 1.57
Electronegativity value of hydrogen= 2.2
Difference of electronegativity value between beryllium and hydrogen= 2.2 – 1.57 = 0.63
Electronegativity difference between Be-H bond calculation of BeH2 molecule

Due to the difference in electronegativity value of greater than 0.5, the Be-H bond of the BeH2 molecule becomes polar. Because of this difference in electronegativity, the BeH2 molecule’s Be-H bond becomes polar. The electronegativity of an atom is the strength with which it may attract bound electron pairs to its side. The polarity of BeH2 is discussed in our previous post.

As a result, the Be-H bond’s dipole moment is high due to the polarization of the bonds, and all Be-H bonds’ dipoles are faced opposite to each other in the linear geometry. The BeH2 molecule’s total dipole moment is predicted to be 0 D. It has a partial negative charge for hydrogen atoms and a partial positive charge for the central beryllium atom.

The electron dot structure of the BeH2 molecule is also known as the BeH2 Lewis structure. It determines the number of outermost valence electrons as well as the electrons engaged in the BeH2 molecule’s bond formation. The outermost valence electrons of the BeH2 molecule must be understood while considering the Lewis structure of the molecule.

The beryllium atom is the middle element in BeH2 molecular geometry, with two electrons in its outermost valence electron shell, whereas the hydrogen atom has one electron in its outermost valence electron shell.

The BeH2 molecule has a total of 4 valence electrons as a result of the foregoing reasoning. With the core central beryllium atom, the two-terminal hydrogen atoms form covalent bonds, leaving the beryllium atom with no lone pairs on it.

The linear geometry and structure of the BeH2 molecules are similar to that of the carbon disulfide (CS2) molecule because no lone pairs of central beryllium atom create interaction with Be-H bond pairs. The bond angle of the H-Be-H bond is approximately 180 degrees. The Be-H bond length is 181 pm(picometer).

To sketch the BeH2 Lewis structure by following these instructions:

Step-1: BeH2 Lewis Structure

To calculate the valence electron of each atom in BeH2, look for its periodic group from the periodic table. The alkaline earth metal and alkaline metal families, which are the second and 17th groups in the periodic table, are both made up of beryllium and hydrogen atoms. In their outermost shells, beryllium and hydrogen have two and one valence electrons, respectively.

Because beryllium and hydrogen are members of the periodic table’s alkaline earth metals and alkaline metal family groups, their valence electrons are two and one, respectively.

Calculate the total number of electrons in the BeH2 molecule’s outermost valence shell. The first step is to determine how many electrons are in the BeH2 Lewis structure’s outermost valence shell. An electron in an atom’s outermost shell is known as a valence electron. It is represented by dots in the BeH2 Lewis diagram. The BeH2 molecule’s core carbon atom can be represented as follows:

Total outermost valence shell electron of beryllium atom in BeH2= 2
Total outermost valence shell electron of hygrogen atom in BeH2= 1
The BeH2 molecule has one central beryllium atom and two hydrogen atoms. Then the total outermost valence shell electrons can be calculated as follows
∴ Total outermost valence shell electrons available for BeH2 Lewis structure( dot structure) = 2 +2*1= 4 valence electrons in BeH2
calculation of total valence electron of BeH2 molecule

Choose the atom with the least electronegative value atom and insert it in the center of the molecular geometry of BeH2. We’ll choose the least electronegative value atom in the BeH2 molecule to place in the center of the BeH2 Lewis structure diagram in this phase. The electronegativity value in periodic groups grows from left to right in the periodic table and drops from top to bottom.

Step-2: BeH2 Lewis Structure

As a result, Beryllium is the first atom in the periodic table’s alkaline earth metal family group. hydrogen is the first member of the alkali metal family. The electronegative value of a beryllium atom is lower than that of a hydrogen atom. Furthermore, Beryllium has a two electrons limit since hydrogen is the most electronegative element in the BeH2 molecule.

In a BeH2 Lewis structure diagram, the beryllium atom can be the center atom. As a result, central beryllium in the BeH2 Lewis structure, with all two hydrogens arranged in the two-terminal of linear geometry.

Step-3: BeH2 Lewis Structure

Connect the exterior and core central atom of the BeH2 molecule with two single bonds (Be-H). In this stage, use two single bonds to connect all two hydrogen atoms on the outside of the BeH2 molecule to the central beryllium atom in the middle.

Count how many electrons from the outermost valence shell have been used in the BeH2 structure so far. Each Be-H bond carries two electrons because each beryllium atom is connected to two hydrogen atoms by two Be-H bonds. Bond pairings are what they’re called.

So, out of the total of 16 valence electrons available for the BeH2 Lewis structure, we used 4 for the BeH2 molecule’s two single (Be-H) bonds. The BeH2 molecule has no lone pair electrons in the center beryllium. We don’t need to put the extra electron in the molecular geometry of BeH2.

Place the valence electrons in the Be-H bond pairs starting with the core beryllium and two hydrogen atoms in the BeH2 molecule. In the BeH2 Lewis structure diagram, we always begin by introducing valence electrons from the central beryllium atom. As a result, wrap around the central beryllium atom’s bond pair valence electrons first.

Beryllium requires 4 electrons in its outermost valence shell to complete the molecular stability. Beryllium already shares 4 electrons thanks to the two single bonds. Then place the valence electron in the hydrogen atom, it placed around one electrons. Totally, 12 valence electrons were placed on the two hydrogen atoms of the BeH2 molecule.

We’ve positioned four electrons around the central beryllium atom, which is represented by a dot, in the BeH2 molecular structure above. The beryllium atom completes its molecular stability in the BeH2 molecule because it possesses 4 electrons in its outermost valence shell.

Count how many outermost valence shell electrons have been used so far using the BeH2 Lewis structure. Four electrons are shown as dots in the BeH2 chemical structure, whereas two single bonds each contain two electrons. The outermost valence shell electrons of the BeH2 molecule are 4 + 0= 4 as a result of the calculation.

So far, we’ve used 4 of the BeH2 Lewis structure’s total eight outermost valence shell electrons.

Complete the middle beryllium atom stability and, if necessary, apply a covalent bond. The core atom in the BeH2 Lewis structure is beryllium, which is bonded to the hydrogen atoms by two single bonds (Be-H). With the help of two single bonds, it already shares four electrons. As a result, hydrogen follows the non-octet rule and has no electrons surrounding it on the two terminals of BeH2.

How to calculate the formal charge in BeH2 Lewis Structure?

The formal charge on the BeH2 molecule’s beryllium central atom often corresponds to the actual charge on that beryllium central atom. In the following computation, the formal charge will be calculated on the central beryllium atom of the BeH2 Lewis dot structure.

To calculate the formal charge on the central beryllium atom of the BeH2 molecule by using the following formula:
The formal charge on the beryllium atom of BeH2 molecule= (V. E(Be)– L.E(Be) – 1/2(B.E))
V.E (Be) = Valence electron in beryllium atom of BeH2 molecule
L.E(Be) = Lone pairs of an electron in the beryllium atom of the BeH2 molecule.
B.E = Bond pair electron in Be atom of BeH2 molecule
calculation of formal charge on beryllium atom in BeH2 molecule

The beryllium core atom (two single bonds connected to hydrogens) of the BeH2 molecule has two valence electrons, zero lone pair electrons, and four bonding electrons. Put these values for the beryllium atom in the formula above.

Formal charge on beryllium atom of BeH2 molecule = (2- 0-(4/2)) =0

In the Lewis structure of BeH2, the formal charge on the central beryllium atom is zero.

Summary:

In this post, we discussed the method to construct the BeH2 Lewis structure. Need to remember that, if you follow above said method, you can construct molecular dot structure very easily.