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Elements and Their Atoms

In chemistry and physics, an element is a substance that cannot be broken down into a simpler substance by chemical means. A pure element is a substance consisting of a single type of atom, with its chemical properties determined by that atom's atomic number, which is the number of protons in its nucleus. Examples of elements include carbon, oxygen, aluminum, iron, gold, copper, mercury, and lead.

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Aditya T.

June 28, 2021

Can you explain about atomic number,mass number and isotypes in detail?

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Aditya T.

June 28, 2021

Can you explain about atomic number,mass number and isotypes in detail?

AT

Aditya T.

June 28, 2021

Can you explain about atomic number,mass number and isotypes in detail?

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Nelson K.

July 26, 2021

Please can I define the mass number as the total number of particles found in the nucleus of an aatom

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Barre A.

September 21, 2021

Which of the following is not a product of glycolysis

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Barre A.

September 21, 2021

Which of the following is not a product of glycolysis

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Barre A.

September 21, 2021

Which of the following is not a product of glycolysis

BA

Barre A.

September 21, 2021

Which of the following is not a product of glycolysis

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Barre A.

September 21, 2021

BA

Barre A.

September 21, 2021

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Barre A.

September 21, 2021

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Emily T.

University of Wisconsin - Madison

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Julie G.

Millikin University

Dr. Bridgette D.

University of North Carolina at Wilmington

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Video Transcript

Welcome to our online lecture, Siris for Biology. 101 Today we'll have our first lecture, which will cover the basics elements and their atoms. So let's get right to it. We know that organisms are composed of matter, and matter is anything that takes up space and has mass. So Iraq will be considered matter because it takes of space and has a mess. Now we know that there is going to be another subdivision to matter. It's not just matter, and that's it. We know that matter is made up of elements so that rock is going to consist of these components, individual elements and compounds that will make up that piece of matter or that rock. So let's define what an element is. An element is going to be any substance that cannot be broken down to other substances, so you could consider it a fundamental substance that cannot be broken down any further by conventional chemical reactions. So let's give an example of what element is the first one that comes to mind would be carbon, because carbon is going to be responsible for all of organic chemistry. Every single compound or molecule in organic chemistry will involve carbon, so carbon is going to be really important to sustaining life. And then also we have oxygen that we know that we need to breathe in order to sustain life and be able to respirator, perform side of the respiration, extract energy out of glucose, make a teepee, and we'll be able to discuss all of this in the context of all these elements. And then we could think of an inorganic element such as hydrogen. And we know that hydrogen, of course, is going to bond with carbon and oxygen to form these organic compounds. Now what we have listed out here are all elements. Let's talk about how we're going to combine elements to form new substances or new kinds of matter so we can take elements, and we conform a compound from either two or more of these elements. So first, let's define what a compound is, and a compound is going to be a substance that consists of two or more different elements combined in a fixed ratio. And this fixed ratio is very important because if we have a known ratio, we can always make the same kind of compound each time. For example, let's take a look at and a CEO or sodium chloride table salt. So N. A C L is going to be composed of two elements. Sodium, which is N A. And chlorine, which is CEO. And these were going to be the, um, the symbols used on our periodic table to define these two elements. So Anna and CEO and when these two combined in a 1 to 1 fixed ratio. So these will combined in a 1 to 1 ratio. That is how we form and a C. L or table salt. And we know that this combination will always produce table salt. There's no mystery to it, and a lot of the chemistry behind the biology of life is going to kind of demystify all these things that occur around us. So, for example, once again with the sodium chloride, we know that every single time we combine sodium and chloride, these two elements together, then we are always going to be forming and a c l or table salt, and there are other combinations that can occur. So, for example, if we have a molecule, then a molecule will involve a a different kind of a combination, and we'll get into the different bonding in another lecture. But just to give you a preview, it all comes down to the electrons that are either transferred or shared. So in a compound we are going to transfer electrons from one Adam or one element to the other. Whereas if we are to define a molecule, then we know that for our molecule, we are going to be actually sharing electrons and just to define what a molecule is, is basically going to be the same as a compound. Like we said, a substance consisting of two or more elements combined in the fixed ratio, the same definition will apply for molecule. The only difference is instead of, as we said, transferring electrons in the compound, we will be sharing electrons in our molecules so we could just say that the definition will be the same as for our compound. And remember, it's really important to know that there's going to be this fixed ratio here because this fixed ratio is responsible for maintaining the fact that we always will produce the same molecule or compound. If we are to take these different elements and combine them in this ratio, we always know what the product will be. So this is what we have so far matter elements, compound and molecule. But let's also talk a little bit about the way that atoms are structured. So we talked about the transfer of electrons and sharing electrons. But what are electrons and what do they look like? How do we see them in Adam's? What form do they take? So let's just talk about that a little bit. So we know that if we are to look at an atom when we're just gonna draw this out right here, we know that there's going to be a nucleus. And then there's going to be what is called an electron cloud. And earlier, back in the 19 thirties, 19 twenties, people believed that there was a nucleus and that these electrons would travel orbits around the nucleus on fixed paths. And, of course, we know that the nucleus is extremely small in comparison to the, um, overall electron cloud or the orbits that people initially thought the electrons would take. But this model right here on the right was Krugman false, because we now know that there is the boar model of the atom, where we have an electron cloud, so as opposed to these fixed orbits. So here we had electron orbits. Now we know that instead of those orbits, we have an electron cloud where an electron has different probabilities of ending up based on its location and distance from the center nucleus. So let's just label this center right here as the nucleus. We'll take a closer look at that nucleus in a second, but just to show you, these electrons can be anywhere within this cloud, and there's different probabilities of them being, uh at different points away from the nucleus. But we could just approximate that. Most likely the electrons would be somewhere around in this region. So the electrons will stay most of the time along this path, and we know that our electrons are going to be negatively charged where, as our nucleus will have an overall positive charge. So let's talk about the players here. So we already mentioned electrons. Let's just define what an electron is. An electron is going to have very little mass, so we're talking about electrons here. Electron is going to be a particle in atomic particle with below mass and a negative charge, and it's important to note that it will be found in the electron cloud. And when I draw out this e minus, that is going to be the shorthand for electron Now. We also know that within this nucleus we said that it has an overall positive charge. But within the nucleus we will find too different particles. There will be protons and there will be neutrons. So let's talk about each one. So our proton will be a nuclear particle because it's within the nucleus. It's a nuclear particle with a mass of one atomic mass unit, and it will have a positive charge. And if we compare that with a neutron, then we know that the neutron will also be a nuclear particle with a massive approximately one atomic mass unit and a neutral or no charge. So let's just take a little pop quiz here. What is going to be found within the nucleus? And we know that the answer is the proton and the neutron, whereas will be found outside the nucleus. What will be the electron and the number of protons, electrons and neutrons that you have will be based on each atom. So let's take, for example, the hydrogen atom. We know that the hydrogen atom will have one proton. It will also have one new charm, and it will have one electron. So the charges balance out. And we know that on any Adam if it is going to be a regular Adam with no added electrons then and if it's not an isotope, then it will have a neutral charge or charge of zero in overall charge of zero, because the number of protons in the numbers of neutrons will be equal. So that will cover everything we have to know about Adams and Elements, Um, and the way those functions. But just to go a little bit deeper into the way that we can describe, um, the atom that we're talking about there are multiple different ways that we can talk about it. So let's start off with what is called the atomic number. So our atomic number is going to be the number of protons that is going to be unique for our element. And this is a very important aspect right here that it is unique to the element in question because each element will be different in the number of protons that it has. So, for example, hydrogen has one proton and P plus is going to represent Proton, whereas helium has two protons and we can keep going up with this number. We know that carbon has six protons, and if we are referring to oxygen, then that has eight protons and all of this could be found in the periodic table, and specifically, the number that you see on the periodic table will represent the atomic number. To go along with this, we know that there will also be a mass number and that mass number is going to tell us the number of neutrons and protons combined together. And as we said, remember up here the proton and the neutron both have a mass of one atomic mass unit. So if we are to think about what would be the mass number well, if we take the some of the proton and neutron or n raised to the zero, that's ah neutron shorthand. Some of the proton and neutron amounts will give us the mass number. So, for example, helium has two protons and two neutrons. Mass number equals what? Well, we just take the two and we add it to the to and we get four. So the mass number equals four. And we can actually write out the mass number and the atomic number in a manner that will represent both figures alongside the shorthand or the, uh, symbolism for that element. So, for example, taking the same helium right here, we know that the abbreviation for helium is H E. And we can write out our mass number right here. So that would be our mass number. And then we would write our atomic number down here. So putting it together with the actual numbers, we would have the mass number of four above our atomic number of two and then to the right would be our symbolism for helium. So this is how we would represent helium as an element if we're trying to talk about it in that kind of context. And finally we can talk about just the way in which different elements can have different numbers of neutrons and they'll still remain the right element because, as we said, what is going to determine what kind of element we have. Well, it's going to be the atomic number because it is unique to the element and that is the number of protons that that element has. So it's very important that we have the correct number of protons to, um, show that, for example, we have helium, but we can have a varying number of electrons and neutrons. So if we are to refer to this term called isotopes, these will be different variations of the same element that have different numbers of neutrons. So they'll have a different mass number. So, for example, we know that carbon has six protons, six neutrons and then six electrons to go with it. But if we are just referring to this protons and the neutrons, since we're looking at that nucleus, this is going to have a mass number of 12, and the atomic number is going to equal six. So how can we increase that mass number but maintain the same number of protons? Will we have to increase the number of neutrons? So if we increase it, we can increase it to eight neutrons and maintain the six same protons. Now we have a mass number of 14 and atomic number of six because the six protons remains unchanged between the two. So what does this tell us? Well, now we have made a nice tobe because the original carbon had six neutrons, but now it's increased to eight. So this would be an example of an isotope where we have different versions of the same carbon because it's still carving because the number of protons has not changed. But in this case we have increased the number of neutrons. So thus we have created a new isotope and weaken denote these different isotopes by this kind of symbolism. So the first one would be carbon Dash 12 because its mass number was 12, whereas our ah second one would be denoted by carbon or C Dash 14 because its mass number was 14 and these two together are going to be isotopes who are different versions of the same element with different mass numbers. So this concludes our overview of the basics atoms and their elements, elements in their atoms and just the framework that we need in order to build upon the chemistry behind the biology of life.