Botulinum Toxin H Chemical Formula

Rejuvenating Skin Care Recipes

Homemade Skin Care Recipes

Get Instant Access

It consists of four hydrogen atoms covalently bonded to a single nitrogen (N) atom, and it has a net electrical charge of +1 for the whole cation, as shown by its Lewis formula above.

How Move Toxic Material

The transfer of two electrons from yields an ion of Mg2+ and one of an atom of Mg to an O atom O2- in the compound MgO.

Formation of ionic MgO as shown by Lewis formulas and symbols. In MgO, Mg has lost 2 electrons and is in the +2 oxidation state {Mg(II)} and O has gained 2 electrons and is in the -2 oxidation state.

Figure 1.7 Ionic bonds are formed by the transfer of electrons and the mutual attraction of oppositely charged ions in a crystalline lattice.

1.3.4 Summary of Chemical Compounds and the Ionic Bond

The preceding several pages have just covered material on chemical compounds and bonds that is essential for understanding chemistry. To summarize:

• Atoms of two or more different elements can form chemical bonds with each other to yield a product that is entirely different from the elements. Such a substance is called a chemical compound.

• The formula of a chemical compound gives the symbols of the elements and uses subscripts to show the relative numbers of atoms of each element in the compound.

• Molecules of some compounds are held together by covalent bonds consisting of shared electrons.

• Another kind of compound is composed of ions consisting of electrically charged atoms or groups of atoms held together by ionic bonds that exist because of the mutual attraction of oppositely charged ions.

1.3.5 Molecular Mass

The average mass of all molecules of a compound is its molecular mass (formerly called molecular weight). The molecular mass of a compound is calculated by multiplying the atomic mass of each element by the relative number of atoms of the element, then adding all the values obtained for each element in the compound. For example, the molecular mass of NH3 is 14.0 + 3 x 1.0 = 17.0. For another example, consider the following calculation of the molecular mass of ethylene, C2H4:

1. The chemical formula of the compound is C2H4.

2. Each molecule of C2H4 consists of two C atoms and four H atoms.

3. From the periodic table or Table 1.2, the atomic mass of C is 12.0 and that of H is 1.0.

4. Therefore, the molecular mass of C2H4 is

From 2 C atoms v-

From 4 H atoms

1.3.6 Oxidation State

The loss of two electrons from the magnesium atom, as shown in Figure 1.7, is an example of oxidation, and the Mg2+ ion product is said to be in the +2 oxidation state. (A positive oxidation state or oxidation number is conventionally denoted by a roman numeral in parentheses following the name or symbol of an element, as in magnesium(II) and Mg(II).) In gaining two negatively charged electrons in the reaction that produces magnesium oxide, the oxygen atom is reduced and is in the -2 oxidation state. (Unlike positive oxidation numbers, negative ones are not conventionally shown by roman numerals in parentheses.) In chemical terms, an oxidizer is a species that takes electrons from a reducing agent in a chemical reaction. Many hazardous waste substances are oxidizers or strong reducers, and oxidation-reduction is the driving force behind many dangerous chemical reactions. For example, the reducing tendencies of the carbon and hydrogen atoms in propane cause it to burn violently or explode in the presence of oxidizing oxygen in air. The oxidizing ability of concentrated nitric acid, HNO3, enables it to react destructively with organic matter, such as cellulose or skin. Strong oxidants such as 30% hydrogen peroxide, H2O2, are classified as corrosive poisons because of their ability to attack exposed tissue.

Covalently bonded atoms that have not actually lost or gained electrons to produce ions are also assigned oxidation states. This can be done because in covalent compounds electrons are not shared equally. Therefore, an atom of an element with a greater tendency to attract electrons is assigned a negative oxidation state, compared to the positive oxidation state assigned to an element with a lesser tendency to attract electrons. For example, Cl atoms attract electrons more strongly than H atoms do, so in hydrogen chloride gas, HCl, the Cl atom is in the -1 oxidation state and the H atoms are in the +1 oxidation state. Electronegativity values are assigned to elements on the basis of their tendencies to attract electrons.

The oxidation state (oxidation number) of an element in a compound may have a strong influence on the hazards and toxicities posed by the compound. For example, chromium from which each atom has lost three electrons to form a chemical compound, designated as chromium(III) or Cr(III), is not toxic, whereas chromium in the +6 oxidation state (Cr(VI), chromate) is regarded as a cancer-causing chemical when inhaled.

Was this article helpful?

+2 0
Anti Ageing And Skincare Made Easy

Anti Ageing And Skincare Made Easy

Not Too Happy With Your Dull, Lifeless Skin? Do You Get Self-Conscious About Your Looks Especially The Evening You Need To Attend A Party? Are You Frustrated With Your Futile Attempts To Get Back Your Once-Glowing Skin? Fret Not Finally Discover How You Can Bring In A Natural Glow To Your Skin And Uncover Super Effective Tips And Strategies To Enliven Your Looks Once Again Enjoy A Perfectly Healthy Skin That Breathes With HappinessAnd Make Every Head Turn To Take A Second Look At You

Get My Free Ebook

Post a comment