Tuesday, January 13, 2015
Saturday, October 19, 2013
Electron shells and energy levels
The electrons of an atom orbit the nucleus in a circular pattern. Some are closer to the nucleus while others are not. We can find out how close the electrons are to the nucleus by determining which electron shell or energy level they belong to. Electron shells are like rings that continue outward away from the nucleus.
Each electron shell holds a set number of electrons with the smallest ring (the one closest to the nucleus) holding the least electrons. There are six electron shells that can be represented with letters or numbers. They can be numbered 1-6 with 1 being closest to the nucleus, or can be represented with the letters K-P with K being closest to the nucleus.
To be continued...
Each electron shell holds a set number of electrons with the smallest ring (the one closest to the nucleus) holding the least electrons. There are six electron shells that can be represented with letters or numbers. They can be numbered 1-6 with 1 being closest to the nucleus, or can be represented with the letters K-P with K being closest to the nucleus.
To be continued...
Calculating atomic mass units
The atomic mass unit or amu relates to an element's average mass.
Before calculating the amu it is vital to understand that an element can have several different masses. This is because an element may have atoms that have different numbers of neutrons which are called isotopes. Each element has its own number of isotopes. The amu represents an average of an element and its different isotopes.
To calculate the amu of an element you must first identify the mass of the different isotopes and the abundance in which they naturally occur in nature. Next, take each isotope's mass and multiply it by the extent that it occurs in nature. Make sure that you move the decimal two places to the left to turn your percentage into a decimal before multiplying. Once you have multiplied each isotope by its percentage in which it occurs in nature, you add these numbers together to get the amu.
For example, oxygen has three naturally occurring isotopes. These are O16, O17, and O18.
O16's mass is 15.99491463 and occurs at 99.757%. (15.99491463 x .99757 = 15.9560469874)
O17's mass is 16.9991312 and occurs at 0.038%. (16.9991312 x .00038= 0.00645966985)
O18's mass is 17.9991603 and occurs at 0.205%. (17.9991603 x .00205= 0.03689827861)
15.9560469874 + 0.00645966985 + 0.03689827861 = 15.9994049359
15.9994 is the amu of oxygen.
Before calculating the amu it is vital to understand that an element can have several different masses. This is because an element may have atoms that have different numbers of neutrons which are called isotopes. Each element has its own number of isotopes. The amu represents an average of an element and its different isotopes.
To calculate the amu of an element you must first identify the mass of the different isotopes and the abundance in which they naturally occur in nature. Next, take each isotope's mass and multiply it by the extent that it occurs in nature. Make sure that you move the decimal two places to the left to turn your percentage into a decimal before multiplying. Once you have multiplied each isotope by its percentage in which it occurs in nature, you add these numbers together to get the amu.
For example, oxygen has three naturally occurring isotopes. These are O16, O17, and O18.
O16's mass is 15.99491463 and occurs at 99.757%. (15.99491463 x .99757 = 15.9560469874)
O17's mass is 16.9991312 and occurs at 0.038%. (16.9991312 x .00038= 0.00645966985)
O18's mass is 17.9991603 and occurs at 0.205%. (17.9991603 x .00205= 0.03689827861)
15.9560469874 + 0.00645966985 + 0.03689827861 = 15.9994049359
15.9994 is the amu of oxygen.
Friday, October 18, 2013
Atomic Structure
Atoms are often thought of as the smallest components of life. They are what make the elements, and atoms of the same element have the same properties.
Every atom can be broken down into subatomic particles. The three basic ones are the proton, neutron, and electron. Each subatomic particle has its own electrical charge. The proton has a positive charge, the neutron is neutral, and the electron has a negative charge. Each of these is needed to maintain the balance that holds an atom together.
To explain further, the atom consists of a nucleus. The protons and neutrons reside inside of the nucleus and are called nucleons. The electrons move around the nucleus in energy levels or energy shells. Energy levels can be described as the path in which the electron orbits the nucleus, and there can be more than one energy level depending on the element.
Each electron is repelled by other electrons, and protons are also repelled by other protons. Electrons and protons however are attracted to each other and this is important as their attraction is what holds the atom together. The electrons orbit freely around the atom, but are held close to it because of their attraction to the protons within the nucleus. Additionally, the electrons are evenly spaced out around the nucleus because they are repelled by the other electrons. Furthermore, an atom is considered to be stable when it has the same amount of protons and neutrons.
Most of the atom's mass comes from the nucleus as protons and neutrons weigh significantly more than the electrons.
Every atom can be broken down into subatomic particles. The three basic ones are the proton, neutron, and electron. Each subatomic particle has its own electrical charge. The proton has a positive charge, the neutron is neutral, and the electron has a negative charge. Each of these is needed to maintain the balance that holds an atom together.
To explain further, the atom consists of a nucleus. The protons and neutrons reside inside of the nucleus and are called nucleons. The electrons move around the nucleus in energy levels or energy shells. Energy levels can be described as the path in which the electron orbits the nucleus, and there can be more than one energy level depending on the element.
Each electron is repelled by other electrons, and protons are also repelled by other protons. Electrons and protons however are attracted to each other and this is important as their attraction is what holds the atom together. The electrons orbit freely around the atom, but are held close to it because of their attraction to the protons within the nucleus. Additionally, the electrons are evenly spaced out around the nucleus because they are repelled by the other electrons. Furthermore, an atom is considered to be stable when it has the same amount of protons and neutrons.
Most of the atom's mass comes from the nucleus as protons and neutrons weigh significantly more than the electrons.
Thursday, October 17, 2013
Understanding the different forms of matter
The earth and its objects are composed of many different kinds of matter. In this section I will list the different types of matter and identify reasons why they are different. There are several factors to keep in mind when distinguishing between different types of matter. For example, is it homogeneous or heterogeneous, is its composition definite or variable, are there more than one atom or element involved, and is a substance chemically or physically combined? Here I will define and explain these terms.
Starting off, the earth is made of two very different forms of matter. These are matter and radiant energy. One of the most important differences between these two are the rate at which they travel. Matter travels less than the velocity of light and radiant energy travels with the velocity of light. The velocity of light is a fundamental constant in which is 2.9979 x 10E8. One interesting similarity between the two is that both matter and radiant energy contain mass. Everything that has mass is influenced by the force of gravity. It was once thought that only matter contained mass but in 1905 Albert Einstein discovered that radiant energy also has mass. After this finding the law of conservation of matter and the law of conservation of energy were both replaced by the law of conservation of mass which states that the mass of the reactants or starting material must equal the mass of the products. (Pauling 1-2)
MATTER
The word material is generally used to describe any type of physical matter. Materials are next classified by whether or not they are pure substances or mixtures.
SUBSTANCES
Substances are different types of matter that are homogeneous and have reasonably definite chemical compositions. Substances cannot be broken down by physical processes. The word substance is often used loosely to describe lots of different materials but is correctly defined when referring to a particular kind of matter consisting of uniform properties.
Elements are made of atoms which can be broken down further into subatomic particles. There are three distinct subatomic particles. These are known as the proton (which carries a positive charge), the neutron (which is neutral), and the electron (which carries a negative charge). Each element is composed of only one type of atom.
Molecules are groups of atoms that are tied in a definite arrangement and are different from compounds because they are composed of more than one atom, but not more than one element. All compounds are molecules but not all molecules are compounds.
Compounds consist of two or more elements that have a definite chemical composition making them a homogeneous material that is chemically combined.
Minerals are made of any chemical element, compound, or other homogeneous material that occur naturally as a product of inorganic processes.
MIXTURES
Mixtures contain different kinds of matter that are physically mixed but not chemically combined.
The homogeneity or heterogeneity of a material is an important part in classification when referring to mixtures. Homogeneous materials have the same properties throughout. This means that one scoop of the material would contain the same properties throughout. Heterogeneous materials are not uniform throughout. They may have localized areas with different properties.
Solutions are similar to mixtures because they also contain different kinds of matter, however solutions are always homogeneous. Substances as we know are also homogeneous. Solutions are different from substances because they contain more than one kind of matter and the composition is variable.
Works Cited:
Pauling, Linus. General Chemistry. New York: Dover Publications INC, 1988. Print.
Starting off, the earth is made of two very different forms of matter. These are matter and radiant energy. One of the most important differences between these two are the rate at which they travel. Matter travels less than the velocity of light and radiant energy travels with the velocity of light. The velocity of light is a fundamental constant in which is 2.9979 x 10E8. One interesting similarity between the two is that both matter and radiant energy contain mass. Everything that has mass is influenced by the force of gravity. It was once thought that only matter contained mass but in 1905 Albert Einstein discovered that radiant energy also has mass. After this finding the law of conservation of matter and the law of conservation of energy were both replaced by the law of conservation of mass which states that the mass of the reactants or starting material must equal the mass of the products. (Pauling 1-2)
MATTER
The word material is generally used to describe any type of physical matter. Materials are next classified by whether or not they are pure substances or mixtures.
SUBSTANCES
Substances are different types of matter that are homogeneous and have reasonably definite chemical compositions. Substances cannot be broken down by physical processes. The word substance is often used loosely to describe lots of different materials but is correctly defined when referring to a particular kind of matter consisting of uniform properties.
Elements are made of atoms which can be broken down further into subatomic particles. There are three distinct subatomic particles. These are known as the proton (which carries a positive charge), the neutron (which is neutral), and the electron (which carries a negative charge). Each element is composed of only one type of atom.
Molecules are groups of atoms that are tied in a definite arrangement and are different from compounds because they are composed of more than one atom, but not more than one element. All compounds are molecules but not all molecules are compounds.
Compounds consist of two or more elements that have a definite chemical composition making them a homogeneous material that is chemically combined.
Minerals are made of any chemical element, compound, or other homogeneous material that occur naturally as a product of inorganic processes.
MIXTURES
Mixtures contain different kinds of matter that are physically mixed but not chemically combined.
The homogeneity or heterogeneity of a material is an important part in classification when referring to mixtures. Homogeneous materials have the same properties throughout. This means that one scoop of the material would contain the same properties throughout. Heterogeneous materials are not uniform throughout. They may have localized areas with different properties.
Solutions are similar to mixtures because they also contain different kinds of matter, however solutions are always homogeneous. Substances as we know are also homogeneous. Solutions are different from substances because they contain more than one kind of matter and the composition is variable.
Works Cited:
Pauling, Linus. General Chemistry. New York: Dover Publications INC, 1988. Print.
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