What Is Salicylic Acid ?

What Is Salicylic Acid ?

 Softens the skin layers that form a wart so that the wart can be rubbed off with a pumice stone or file. Repeatedly irritates a wart, which is thought to trigger an immune system . response. A heightened immune response fights the human papilloma virus. that causes wart growth.

Salicylic acid may work even better if you remove the dead skin from the top of the wart. Soak the wart with water to soften it. Then use a pumice stone, nail file, or stiff brush to rub off the top layer of skin. (Don't use the stone, file, or brush for anything else.) When you put on the medicine, it will penetrate deeper into the wart tissue. belongs to the beta hydroxy acid, BHA, group. Its peel is produced The acid is an organic acid that is derived from the bark of willow tree and it synthetically.  Salicylic acid is poorly soluble in water and it has a colorless crystalline structure.  Its molecular structure is larger than the alpha hydroxy acids.   Its effect as a pain reliever and anti-inflammatory agent is established in medical use.  When it comes to treat skin abnormalities, it is found equally effective since it can penetrate the skin pores that contain sebum.  Though it can’t influence the production of sebum or P. acne bacteria, it is found effective to cleanse the pores that carry excess of such substances. Salicylic acid is used in many skin care products such as moisturizers, cleansers, cream, lotions, etc.  Its peeling properties make it one of the favorable choices of cosmetic acids that are widely used in skin care.   

Benefits of Salicylic Acid

The acid is a known cosmetic acid that can especially be used to treat eczema, acne, psoriasis, dandruff, and warts.

Since it can cause the outer skin layer to become loose, the damaged skin layer is exfoliated easily.  This results in skin pores to be free from any debris, and in less visible whiteheads and blackheads, acne, and some other skin abnormalities.  Moreover, the skin color can be improved by the use of this acid. For sensitive skin, salicylic acid peel proves itself better than glycolic or lactic acid treatment.

Side Effects of Salicylic Acid

Side effects of minor nature can be experienced from the treatment of salicylic acid.  You can experience itching, burning, and other discomforts of mild nature.  Sometimes the skin can dry out excessively that leads to flaking.  If you find yourself with such discomforts and if they don’t seem to be normal, increase spacing between two treating sessions; if you use it daily, then use it ever alternate day. If you experience dizziness, headache, nausea, of such abnormal side effects, stop using the product containing salicylic acid and call a doctor immediately.  This, however, isn’t a common happening. When you find things aren’t normal or when you feel the discomfort not tolerable, which could happen if the reaction is severe, better consult a doctor and avoid using any product containing salicylic acid until they are cleared by a skin specialist.

Throughout life, sometimes change is the only thing that seems constant. Change has come to my life in many ways, in myself and in my surroundings

What special courses do you need to take in high school so that you can get a college degree in chemistry or chemical engineering? Basically, it boils down to science and math. You can talk with your guidance counselor and teachers for more information. Also, always feel free to contact the department chair in the college program that interests you to get more detailed advice. College catalogs are also a good source for learning about requirements. red cat

Introduction to the Periodic Table

People have known about elements like carbon and gold since ancient time. The elements couldn't be changed using any chemical method. Each element has a unique number of protons. If you examine samples of iron and silver, you can't tell how many protons the atoms have. However, you can tell the elements apart because they have different properties. You might notice there are more similarities between iron and silver than between iron and oxygen. Could there be a way to organize the elements so you could tell at a glance which ones had similar properties?

What is the Periodic Table?

Dmitri Mendeleev was the first scientist to create a periodic table of the elements similar to the one we use today. You can see Mendeleev's original table (1869). This table showed that when the elements were ordered by increasing atomic weight, a pattern appeared where properties of the elements repeated periodically. This periodic table is a chart that groups the elements according to their similar properties.

Why was the Periodic Table Created?

Why do you think Mendeleev made a periodic table? Many elements remained to be discovered in Mendeleev's time. The periodic table helped predict the properties of new elements.
Mendeleev's Periodic Table
Compare the modern periodic table with Mendeleev's table. What do you notice? Mendeleev's table didn't have very many elements, did it? He had question marks and spaces between elements, where he predicted undiscovered elements would fit.
Discovering Elements
Remember changing the number of protons changes the atomic number, which is the number of the element. When you look at the modern periodic table, do you see any skipped atomic numbers that would be undiscovered elements? New elements today aren't discovered. They are made. You can still use the periodic table to predict the properties of these new elements.
Element Properties and Trends
The periodic table helps predict some properties of the elements compared to each other. Atom size decreases as you move from left to right across the table and increases as you move down a column. Energy required to remove an electron from an atom increases as you move from left to right and decreases as you move down a column. The ability to form a chemical bond increases as you move from left to right and decreases as you move down a column.

Today's Periodic Table

The most important difference between Mendeleev's table and today's table is the modern table is organized by increasing atomic number, not increasing atomic weight. Why was the table changed? In 1914, Henry Moseley learned you could experimentally determine the atomic numbers of elements. Before that, atomic numbers were just the order of elements based on increasing atomic weight. Once atomic numbers had significance, the periodic table was reorganized.

Periods and Groups

Elements in the periodic table are arranged in periods (rows) and groups (columns). Atomic number increases as you move across a row or period.

Periods

Rows of elements are called periods. The period number of an element signifies the highest unexcited energy level for an electron in that element. The number of elements in a period increases as you move down the periodic table because there are more sublevels per level as the energy level of the atom increases.

Groups

Columns of elements help define element groups. Elements within a group share several common properties. Groups are elements have the same outer electron arrangement. The outer electrons are called valence electrons. Because they have the same number of valence electrons, elements in a group share similar chemical properties. The Roman numerals listed above each group are the usual number of valence electrons. For example, a group VA element will have 5 valence electrons.

Representative vs. Transition Elements

There are two sets of groups. The group A elements are called the representative elements. The group B elements are the nonrepresentative elements.

What is on the Element Key?

Each square on the periodic table gives information about an element. On many printed periodic tables you can find an element's symbol, atomic number, and atomic weight.

Classifying Elements

Elements are classified according to their properties. The major categories of elements are the metals, nonmetals, and metalloids.

Metals

You see metals every day. Aluminum foil is a metal. Gold and silver are metals. If someone asks you whether an element is a metal, metalloid, or non-metal and you don't know the answer, guess that it's a metal.

What are Properties of Metals?

Metals share some common properties. They are lustrous (shiny), malleable (can be hammered), and are good conductors of heat and electricity. These properties result from the ability to easily move the electrons in the outer shells of metal atoms.

What are the Metals?

Most elements are metals. There are so many metals, they are divided into groups: alkali metals, alkaline earth metals, and transition metals. The transition metals can be divided into smaller groups, such as the lanthanides and actinides.

Group 1: Alkali Metals

The alkali metals are located in Group IA (first column) of the periodic table. Sodium and potassium are examples of these elements. Alkali metals form salts and many other compounds. These elements are less dense than other metals, form ions with a +1 charge, and have the largest atom sizes of elements in their periods. The alkali metals are highly reactive.

Group 2: Alkaline Earth Metals

The alkaline earths are located in Group IIA (second column) of the periodic table. Calcium and magnesium are examples of alkaline earths. These metals form many compounds. They have ions with a +2 charge. Their atoms are smaller than those of the alkali metals.

Groups 3-12: Transition Metals

The transition elements are located in groups IB to VIIIB. Iron and gold are examples of transition metals. These elements are very hard, with high melting points and boiling points. The transition metals are good electrical conductors and are very malleable. They form positively charged ions.
The transition metals include most of the elements, so they can be categorized into smaller groups. The lanthanides and actinides are classes of transition elements. Another way to group transition metals is into triads, which are metals with very similar properties, usually found together.

Metal Triads

The iron triad consists of iron, cobalt, and nickel. Just under iron, cobalt, and nickel is the palladium triad of ruthenium, rhodium, and palladium, while under them is the platinum triad of osmium, iridium, and platinum.

Lanthanides

When you look at the periodic table, you'll see there is a block of two rows of elements below the main body of the chart. The top row has atomic numbers following lanthanum. These elements are called the lanthanides. The lanthanides are silvery metals that tarnish easily. They are relatively soft metals, with high melting and boiling points. The lanthanides react to form many different compounds. These elements are used in lamps, magnets, lasers, and to improve the properties of other metals.

Actinides

The actinides are in the row below the lanthanides. Their atomic numbers follow actinium. All of the actinides are radioactive, with positively charged ions. They are reactive metals that form compounds with most nonmetals. The actinides are used in medicines and nuclear devices.

Groups 13-15: Not all Metals

Groups 13-15 include some metals, some metalloids, and some nonmetals. Why are these groups mixed? The transition from metal to nonmetal is gradual. Even though these elements aren't similar enough to have groups contained within single columns, they share some common properties. You can predict how many electrons are needed to complete an electron shell. The metals in these groups are called basic metals.

Nonmetals & Metalloids

Elements that don't have the properties of metals are called nonmetals. Some elements have some, but not all of the properties of the metals. These elements are called metalloids.

What are Properties of Nonmetals?

The nonmetals are poor conductors of heat and electricity. Solid nonmetals are brittle and lack metallic luster. Most nonmetals gain electrons easily. The nonmetals are located on the upper right side of the periodic table, separated from metals by a line that cuts diagonally through the periodic table. The nonmetals can be divided into classes of elements that have similar properties. The halogens and the noble gases are two groups of nonmetals.

Group 17: Halogens

The halogens are located in Group VIIA of the periodic table. Examples of halogens are chlorine and iodine. You find these elements in bleaches, disinfectants, and salts. These nonmetals form ions with a -1 charge. The physical properties of the halogens vary. The halogens are highly reactive.

Group 18: Noble Gases

The noble gases are located in Group VIII of the periodic table. Helium and neon are examples of noble gases. These elements are used to make lighted signs, refrigerants, and lasers. The noble gases are not reactive. This is because they have little tendency to gain or lose electrons.

Hydrogen

Hydrogen has a single positive charge, like the alkali metals, but at room temperature, it is a gas that doesn't act like a metal. Therefore, hydrogen usually is labeled as a nonmetal.

What are the Properties of the Metalloids?

Elements that have some properties of metals and some properties of nonmetals are called metalloids. Silicon and germanium are examples of metalloids. The boiling points, melting points, and densities of the metalloids vary. The metalloids make good semiconductors. The metalloids are located along the diagonal line between the metals and nonmetals in the periodic table.

Common Trends in Mixed Groups

Remember that even in mixed groups of elements, the trends in the periodic table still hold true. Atom size, ease of removing electrons, and ability to form bonds can be predicted as you move across and down the table.

Hydrogen Facts Chemical & Physical Properties of Hydrogen.

Hydrogen Discovery: Cavendish, 1766. Hydrogen was prepared for many years before it was recognized as a distinct element. Hydrogen Electron Configuration: 1s¹
Hydrogen Word Origin: Greek: hydro, water; genes, forming Named by Lavoisier.
Hydrogen Isotopes: Protium (0 neutrons), Deuterium (1 neutron), and Tritium (2 neutrons)
Ground level: 2S_1/2
Ionization potential: 13.5984 ev
Physical form: Colorless gas
Melting point: -259.2°C
Melting point: -259.2°C
Boiling point: -252.762°C
Critical temperature: -240.18°C
Density: 0.082 g/L
Specific heat: 14.304 J/g•K
Valence: 1
Hydrogen Properties: Hydrogen is the most abundant element in the universe. The heavier elements were made from hydrogen or from other elements that were made from hydrogen. Hydrogen is a colorless, odorless, combustible gas. Hydrogen gas is so light and diffusive that uncombined hydrogen can escape from the atmosphere. Hydrogen gas ordinarily is a mixture of two molecular forms, ortho- and para-hydrogen, which differ by the spins of their electrons and nuclei. Normal hydrogen at room temperature consists of 25% of the para form and 75% of the ortho form. The ortho form cannot be prepared in the pure state. Since the two forms of hydrogen differ in energy, their physical properties also differ.
Hydrogen Uses: Hydrogen is important in the proton-proton reaction and carbon-nitrogen cycle. Liquid hydrogen is used in cryogenics and in the study of superconductivity. Great quantities are used for the fixation of nitrogen from the air in the Haber ammonia process. Hydrogen is use in welding, for the hydrogenation of fats and oils, in methanol production, in hydrodealkylation, hydrocracking, and hydrodesulfurization. Other applications include producing rocket fuel, filling balloons, making fuel cells, producing hydrochloric acid, and reducing metallic ores.  is used as a moderator to slow down neutrons and as a tracer. Tritium is used in the production of the hydrogen (fusion) bomb. Tritium is also used in making luminous paints and as a tracer.
Hydrogen Sources: Hydrogen occurs in the free state in volcanic gases and some natural gases. Hydrogen is prepared by steam on heated carbon, decomposition of certain hydrocarbons with heat, action of sodium or potassium hydroxide on aluminum electrolysis of water, or displacement from acids by certain metals.
Other Hydrogen Facts: While about 75% of the universe's elemental mass is hydrogen, hydrogen is relatively rare on Earth. The most common isotope of hydrogen is protium, which has one proton, but no neutrons. Hydrogen gas is extremely flammable. It was associated with the famous explosion of the Hindenburg airship and is used as a fuel by the space shuttle main engine.

What are the percentage contribution of the different Elements in the Human Body ?

Most of the human body is made up of water, H₂O, with cells consisting of 65-90% water by weight. Therefore, it isn't surprising that most of a human body's mass is oxygen. Carbon, the basic unit for organic molecules, comes in second. 99% of the mass of the human body is made up of just six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus.

1. Oxygen (61%)
2. Carbon (23%)
3. Hydrogen (10%)
4. Nitrogen (2.6%)
5. Calcium (1.4%)
6. Phosphorus (1.1%)
7. Potassium (0.20%)
8. Sulfur (0.20%)
9. Sodium (0.14%)
10. Magnesium (0.027%)
11. Copper, Zinc, Selenium, Molybdenum, Fluorine, Chlorine, Iodine, Manganese, Cobalt, Iron (0.70%)
12. Lithium, Strontium, Aluminum, Silicon, Lead, Vanadium, Arsenic, Bromine (trace amounts)

What is an Electron?

An electron is a subatomic particle. Carrying a negative charge, an electron orbits an atom’s nucleus and is bound to it by electromagnetic forces. An electron has a mass that is minuscule in comparison with even the smallest of atoms, coming in at about one thousandth the size of the tiniest atom. The electron is a basic unit of nature, meaning it cannot be broken down into smaller units.
The electron plays a starring roll in many of the interactions we see on a daily basis. For example, electrons are partially responsible for the fact that we can stand on a flat surface and not sink right through it. This occurs as the result of the mutual repulsion of the electrons in both the ground and a person’s shoes. We also depend on electrons for electrical current to power electronic devices. Even televisions rely on electrons to function properly.
G. Johnstone Stoney, an Irish physicist, was credited with introducing the electron concept in 1874, as well as with naming it twenty years later. In 1897, J.J. Thompson, from Cambridge University, discovered that the electron was a subatomic particle. It wasn’t until 1909 that the charge of the electron was measured by Professor Robert Andrews Millikan, an American experimental physicist. He discovered its charge while conducting an oil-drop experiment.

Parts Of An Atom

There are three parts of an atom: protons, neutron, and electrons. Protons have a positive charge, electrons have a negative charge, and neutrons possess no net charge.

Electrons are the smallest parts of the atom. They are the most numerous of the three. It has no known components or substructure, so it is an elementary particle. Its mass is 1/1836 of a proton. It is also considered to be a fermion. It has an antiparticle called the positron. The positron is identical to the electron except that it carries opposite charge. When an electron collides with a positron, both particles will either scatter or be destroyed producing gamma ray photons. Electrons can collide with other particles and be diffracted like light. Two electrons can not occupy the same quantum state based on the Pauli exclusion principle.
               

The proton is the part of an atom that helps to form the nucleus and has a positive charge. Protons must have an equal number of neutrons except int eh hydrogen atom where a single proton exists on its own. A proton is composed of 2 up quarks and one down quark. They are considered to be fermions and baryons. They are held together by the strong nuclear force. The number of protons in the nucleus of an atom determines the atomic number.

A neutron is the part of an atom that holds no charge. Neutrons and protons occur in equal numbers in stable atoms except in hydrogen. Protons and neutrons are often referred to together as nucleons. If there are more neutrons than protons, then the atom is considered an isotope. If an neutron becomes free of its proton, then it becomes unstable, undergoes beta decay, and will disintegrate in an average of 15 minutes. The neutron is also important in nuclear chain reactions: both natural and artificial.

This is only meant to be a basic introduction of the parts of an atom. With additional research you may find yourself immersed for hours in just the introduction to the world of the atom.