The Atomic Structure in the Chemistry Discipline

Chemistry is fun and unique. There are many components that make chemistry what it is. However, there are some basics that are important and need to be learned about before digging deeper into chemistry. First, we have the Scientific Method, this method is an organized approach to solve problems and is used strongly in chemistry. The steps in this approach include Observation, Hypothesis, Experimentation, Analysis, and Concluding Theory. Step one observation is when you use your five senses, sound, smell, sight, taste, and touch to define the problem presented. Step two hypotheses is when you make an educated guess or give a reasonable explanation to the problem observed. Step three, experimentation is when you test each one of your hypotheses to prove or disprove them. Step four analysis is when you compare the results to the hypothesis. Finally step five conclusion theory is when you create a hypothesis based on the experimental evidence. An example could be deciding which fertilizer is best for your plants. Step one observe the options of fertilizer and decide you want the best. Step two makes an educated guess on which fertilizer could be the best. Step three experiments and see which one works the best. Step four collect data and begin to create a conclusion on the best fertilizer. Step five creates a new or improved hypothesis and conclude with the best fertilizer.

Precision and accuracy are very important in chemistry. Precision is the ability to reproduce a result. How close multiple results are to one another. Accuracy is the correction of results. How close or correct the results are to the original value. Examples, Playing darts, precision would mean you hit the board at the same location but no the center (second image). Accuracy would mean you hit the board around the center but not the same location (third image). Both would mean you hit the center at the same location (first image).

Significant Figures also play a huge role in chemistry. They are simply digits that carry meaning. They have a purpose rather than not. Digits can be determined as “significant” if they are non-zeros, captive (middle) zeros, and sometimes trailing zeros. Leading zeros are never significant. Trailing zeros are not counted when they don’t contain decimals. Examples being 155.0, this number contains four significant figures, 1550 contains only three significant figures. Reading equipment with significant figures depends on the device and digits of measurement. In order to find that out, you need to read the first number or measurement and then estimate the second. Example being measuring a pencil. You look at the facts number which is 2 and then estimate the second which is around. 3 or. 4.

Pure substances vs mixtures: Pure substances have a uniform and definite composition. They’re found on the periodic table and are formed when elements chemically combined. Mixtures are two or more different substances mixed together physically. There are two types of mixtures Heterogeneous and Homogeneous. Heterogeneous mixtures can be picked apart examples being pizza or salad, and Homogenous cannot examples being salt water or milk.

Physical and Chemical Changes/Properties: Physical properties are “properties that can be measured or observed without changing the identity of the substance” (dictonary.com), (color, odor, texture, taste, etc.). Physical changes are changes to appearance without changing composition, (melting, freezing, boiling, etc.). Chemical properties are properties that indicate how a substance reacts with other substances, ( flammable, combustible, burnable,etc.). Chemical changes are one or more substances react to form a new substance with different chemical and physical properties, (rusting, burning, corroding, etc.).

History of the Atom

There are many people who lead to the understanding and discovery of the atom and its components. Because of these important people, we are able to understand the matter and life today. The first person to ever think of an atom was Democritus. He was a Greek Philosopher, (not scientist), who thought about the existence of an atom. He even gave it its name, “Atom”. Unfortunately, he had no experimental evidence to back any of his theories up. His theory and discovery has helped the world be more understood and allow us to be able to understand what we are really made up of.

Another important person in history was John Dalton. He was a meteorologist who introduced the atomic theory, which basically sums up Democritus’s ideas and introduced it to chemistry. Unlike Democritus, Dalton had evidence to back up his claims. His theory has four main points. One, all elements are composed of atoms. Two atoms of the same element are identical. Three, atoms of different elements mix or combine in whole-number ratios. Finally four, chemical reactions occur when atoms separate, joined, or rearranged. These four postulates were not all correct however still set a base for chemistry and allowed it to expand. With these ideas, we are able to better understand life and chemistry.

J.J. Thompson was a physicist who discovered and identified the electron. Through the cathode ray tube experiment, he was able to discover the electron. Through the experiment, it was concluded that there was a negatively charged subatomic particle in the tube which is now known as the electron. He also came up with the plum pudding model which shows how electrons are associated with atoms. The diagram shows a solid positively charged sphere with electrons embedded into the sides of it. With his discoveries, scientist and people are able to better understand the atom.

Ernest Rutherford concluded that atoms are mostly made up of empty space. Through his gold foil experiment in which he shot a high beam of alpha particles into gold foil he was able to conduct atoms are mostly empty space. He also concluded there was a small densely packed positive center to an atom which is now known as the nucleus. His discovery helped with the understanding of the atom and their make-up. His discovery helped scientists be more accurate with the understanding of the atom and allows us to properly understand life and chemistry.

Neils Bohr another important person came up with the Bohr model. Bohr proposed that “electrons orbit around the nucleus of an atom in specific/ prescribed orbits and they change orbits when they sense a change of energy” ( Atomic Structure notes day 1). This leads him to come up with the Bohr model which helps describe and calculate this proposition. His diagram helps scientists calculate electron energy easier and more precisely. His model also helps with the understanding of electrons. His model shows how and where electrons function and are located.

Erwin Schrodinger contribute to the quantum theory and construct the Schrodinger equation. The theory helps construct the physical models of subatomic particles. He created an equation that helped calculate wave function and system. His equation is a more detailed and further inept version of the Bohr model. His equation is used to find the specific location and function of electrons in an atom. With his help scientists are now able to easily calculate wave functions and systems along with more precise calculations of electrons and their positions in an atom.

Atomic Structure and Electron Configurations

An Atom is made up of 3 main subatomic particles. These particles are protons, neutrons, and electrons. Protons are positively charged and located in the nucleus of the atom. Neutrons have no charge and are located in the nucleus as well. Electrons are negatively charged and located in the electron cloud which surrounds the nucleus of an atom.

The electron is located in the electron cloud. This cloud surrounds the nucleus of an atom and this is where electrons loseley flow. Electrons cannot be pinpointed but there are probable locations. Electron configurations show how electrons are distributed in an atom. We are also able to understand there are energy levels that surround an atom where the electrons are located. Each energy level then contains sublevels, these sublevels provide the possible areas in the energy level where the electron can be located. From there each of the sublevels are oriented differently and each one of these orientations is called an orbital. There are four main types of shapes these orbitals/sublevels cretate, (Spherical or s sublevel, Dumbbell or p sublevel, Clover or d sublevel, and Double Clover or f sublevel).

Light is a very important part of our lives. Without light there would be nothing to see, therefore it is important to understand how it is created. Atoms create colored light when electrons go from the ground state (highly heated) to their normal state. When the electrons are heated they jump energy levels as they gather energy and as they’re returning to their normal state, they release energy in the form of light. When specific elements are heated they produce energy and release it giving off light. The different colors of light are represented by different wavelengths of elements.The emission spectra helps determine the specific amounts of energy being activated and helps determine the color being given off.

Nuclear Chemistry

Nuclear and Chemical Changes are a part of chemistry and can get confused easily. Nuclear changes are changes that happen with the nuclear structure of an atom. These changes can be changed like fission or splitting of a nucleus or an atom, or fusion or combining of neutrons and protons to form heavier atoms. “Changes in temperature, pressure, or the presence of catalysts do not affect nuclear changes” ( nuclear chem. notes day 1). An example of nuclear change would be the fission of Uranium-235 and Plutonium-239. Chemical changes happen when substances combine with each other and create a new substance. Unlike nuclear changes, chemical changes can be affected by catalysts. An example of chemical change would be, fireworks. When different substances collide they create a new substance and give off light.

There are different types of radiation. Some are stronger than others and can cause damage. The three main types of radiation are Alpha radiation (a), Beta radiation (b), and Gamma radiation (y). Alpha radiation is the weakest among the three and is not very harmful unless ingested. Alpha radiation can be blocked off with a sheet of paper and skin as well. Beta radiation is a little stronger than alpha but also us not very harmful. Beta can be blocked by foil or wood. Gamma radiation is most dangerous and strong and can be harmful,because gamma can pass through most objects and things including humans. However it can be stopped to a certain extent by lead. Alpha, Beta, and Gamma radiations are results of nuclear change and are a good example of it as well. The picture shows how harmful each radiation is for humans.

Radiation can be harmful so it is important to protect yourself from Radiation. Alpha radiation is nothing much to worry about as long as it is not ingested. Beta radiation Is a little bit concerning but as long as you wear proper gear when surrounded by it you should be fine. Gamma radiation is rare to come in contact ih but if near make sure to distance yourself and wear proper gear. Make sure to always be aware of your surroundings and always take proper safety measures. The diagram once again shows in detail how far each radiation can harm humans.

Periodic Trends

The Atomic Radius of an atom is another way of describing the size of an atom. “The size of an atom means the measure of the atom or the distance it is found from the nucleus to the surrounding shells” (periodic trends notes day 2). Atomic radius increases going down on the periodic table and decrease going left to right across the table. The picture shows the meaning of “the distance of the atom”.

Ionization Energy (I.E.) is the energy that is required to remove valence electrons from an atom. The I.E. depends on the distance between electrons and nucleus and the nuclear charge of protons. The further the electron from the nucleus the less Ionizing energy is required. The less the electrons are attracted to the protons. This energy is stronger as you move left to right on the periodic table and weaker as you move down the table. More energy is required to remove the second or third election versus the first. The diagram illustrates the increase and decrease of I.E. on the periodic table.

Electronegativity (E.N.) is “the tendency of an element to attract electrons when chemically combined with another element” ( periodic trends notes day 4). ”The electronegativity of an atom is based on the distance of the electrons from the nucleus of an atom and the atoms atomic number” ( periodic trends notes day 4). Like I.E. the closer the electrons to the nucleus the stronger their attraction to the protons in the nucleus. Therefore more E.N. energy is required to remove the valance electrons of an atom. When you moving across (from left to right) on the periodic table the E.N. increase and decrease as you move down the table. This diagram also illustrates the periodic trend of electronegativity.