Could you please explain how electronegativity works and how you find the total electronegativity value of
PO3
K2O
H2S
GIVEN: P- 2.1, O-3.5, K- 0.8, H- 2.1, and S- 2.5
Also how to you tell if the compound is ionic, polar covalent, or non polar covalent?
Thank you!!!
Which of the following statements describes why ion exchange of 99% SiO2 - 1% B2O3 in a salt bath of molten postassium chloride (KCl) is not an effective way to increase the surface strength of the glass sample?
The ion exchange works correctly, however both air-cooling and water-quenching are more efficient ways to induce a surface strengthening effect.
The glass is composed of only 1% B2O3, which is not a large enough proportion of B2O3 to undergo ion exchange, and therefore does not increase the surface strength of the sample effectively.
The potassium ion is smaller than B2O3, so when ion exchange takes place the surface is actually being weakened instead of strengthened.
The sample described above is composed of SiO2 and B2O3. Neither of these components are network modifiers, so ion exchange does not take place to strengthen the surface of the glass.
The surfaces of the glass sample are not cooled quickly enough to create a high internal strain energy that leads to strong surfaces.
You can talk about the electronegativity (EN) of bonds(each bond in a molecule) but I don't know that there is a total EN for molecules.
For PO3, the P atom has EN of 2.1 and O has 3.5, the difference is 1.4. For the H2S molecules, the H-S bond EN difference is 0.4. For the O2 molecule or H2 molecule or N2 molecules the difference (of course) is zero.
As a general rule a bond is about 50% ionic/50% covalent if the EN difference is 1.8 or so. Also, if we are labeling compounds as ionic or covalent, we call those over 1.8 or 1.9 ionic and those under 1.8 or 1.9 covalent. So N2, O2, H2 etc with a zero difference are non-polar covalent, PO3 is near the 50/50 line so the PO3 bond would be a polar covalent bond (actually a little more covalent than 50% and a little less ionic than 50%). I would classify K2O with a difference of 2.7 as ionic. The H-S bond in H2S is almost purely (but not quite) covalent.
Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons towards itself. The electronegativity of an element is determined based on its position on the periodic table. Elements with high electronegativity tend to attract electrons strongly, while elements with low electronegativity do not attract electrons as strongly.
To find the total electronegativity value of a compound, you need to consider the electronegativity values of the individual atoms and their relative quantities in the compound. The total electronegativity value can be calculated by multiplying the electronegativity of each atom by the number of atoms present, and then summing them up.
Let's calculate the total electronegativity value for each compound given:
1. PO3:
P- 2.1
O- 3.5 (three oxygen atoms present)
Total electronegativity = (2.1 * 1) + (3.5 * 3) = 2.1 + 10.5 = 12.6
2. K2O:
K- 0.8 (two potassium atoms present)
O- 3.5
Total electronegativity = (0.8 * 2) + (3.5 * 1) = 1.6 + 3.5 = 5.1
3. H2S:
H- 2.1 (two hydrogen atoms present)
S- 2.5
Total electronegativity = (2.1 * 2) + (2.5 * 1) = 4.2 + 2.5 = 6.7
To determine if a compound is ionic, polar covalent, or nonpolar covalent, you compare the difference in electronegativity between the atoms involved in the bond.
- If the electronegativity difference is very high (usually greater than 1.7), the bond is considered ionic. In such cases, one atom completely transfers an electron to the other, resulting in a fully charged ion.
- If the electronegativity difference is moderate (between 0.5 and 1.7), the bond is considered polar covalent. In this case, the electrons in the bond are unequally shared, resulting in a partial positive and partial negative charge on the atoms.
- If the electronegativity difference is very low (usually less than 0.5), the bond is considered nonpolar covalent. In this case, the electrons in the bond are equally shared, resulting in no significant charge separation.
Based on the given electronegativity values, we can analyze the compounds:
1. PO3:
The electronegativity difference between P and O is 3.5 - 2.1 = 1.4, which falls in the range of polar covalent bonds. Therefore, PO3 is a polar covalent compound.
2. K2O:
The electronegativity difference between K and O is 3.5 - 0.8 = 2.7, which falls in the range of ionic bonds. Therefore, K2O is an ionic compound.
3. H2S:
The electronegativity difference between H and S is 2.5 - 2.1 = 0.4, which falls in the range of nonpolar covalent bonds. Therefore, H2S is a nonpolar covalent compound.
I hope this helps! Let me know if you have any further questions.
Electronegativity is a property that describes the ability of an atom to attract electrons in a chemical bond. It is generally measured on a scale ranging from 0 to 4, with the most electronegative elements, like fluorine, having the highest values.
To find the total electronegativity value of a molecule or compound, you need to look at the individual electronegativity values of the atoms involved and determine the type of chemical bond present.
For example, let's calculate the total electronegativity value for PO3:
- The electronegativity value for phosphorus (P) is given as 2.1.
- The electronegativity value for oxygen (O) is given as 3.5.
Since PO3 has one phosphorus atom and three oxygen atoms, we can calculate the total electronegativity:
Total Electronegativity = (Electronegativity of P) + (3 x Electronegativity of O) = 2.1 + (3 x 3.5) = 2.1 + 10.5 = 12.6
Similarly, for K2O:
- The electronegativity value for potassium (K) is given as 0.8.
- The electronegativity value for oxygen (O) is given as 3.5.
Since K2O has two potassium atoms and one oxygen atom, we can calculate the total electronegativity:
Total Electronegativity = (2 x Electronegativity of K) + (Electronegativity of O) = (2 x 0.8) + 3.5 = 1.6 + 3.5 = 5.1
And for H2S:
- The electronegativity value for hydrogen (H) is given as 2.1.
- The electronegativity value for sulfur (S) is given as 2.5.
Since H2S has two hydrogen atoms and one sulfur atom, we can calculate the total electronegativity:
Total Electronegativity = (2 x Electronegativity of H) + (Electronegativity of S) = (2 x 2.1) + 2.5 = 4.2 + 2.5 = 6.7
Now, let's determine the type of chemical bond (ionic, polar covalent, or nonpolar covalent) based on the total electronegativity value:
- If the total electronegativity difference is large (greater than 1.7), it indicates an ionic bond. In an ionic bond, electrons are transferred from one atom to another.
- If the total electronegativity difference is moderate (between 0.4 and 1.7), it indicates a polar covalent bond. In a polar covalent bond, electrons are shared unequally between atoms, leading to partial positive and partial negative charges.
- If the total electronegativity difference is small (less than 0.4), it indicates a non-polar covalent bond. In a non-polar covalent bond, electrons are shared equally between atoms, resulting in no net charge.
Using the total electronegativity values we calculated earlier:
- PO3: Since the total electronegativity value is 12.6, which is greater than 1.7, it indicates an ionic bond.
- K2O: Since the total electronegativity value is 5.1, which is between 0.4 and 1.7, it indicates a polar covalent bond.
- H2S: Since the total electronegativity value is 6.7, which is between 0.4 and 1.7, it also indicates a polar covalent bond.
So, to summarize:
PO3 has an ionic bond.
K2O and H2S have polar covalent bonds.