GOB Chemistry

Learn the toughest concepts covered in your GOB - General, Organic, and Biological Chemistry class with step-by-step video tutorials and practice problems.

Atoms and the Periodic Table

Periodic Table: Phases (Simplified)

Under standard conditions of temperature and pressure, the elements can exist as solids, liquids or gases.

3 Phases of Matter



Periodic Table: Phases (Simplified) Concept 1

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So at standard room temperature we have 25 degrees Celsius, and at standard pressure we have what's called one atmosphere. Atmosphere is just ah, unit for pressure. We'll go in greater detail on that particular unit for pressure. When we get to a chapter on gas is but just realize here, when we say standard room temperature and standard pressure, it's 25 degrees Celsius and one atmosphere. Now, under these conditions, the elements can exist under three states of matter, so we know we have solids, liquids and gasses when it comes to solids, solids. If we look here on the left side, you can see that in this image, all of our atoms are neatly packed next to each other tightly. That's because solids maintain a fixed shape and volume. Yeah, liquids. On the other hand, we can see here in this image of the liquid, all of them are not locked in grid like they were in a solid and the arrows. You show that the atoms move in random directions. They're still in contact with one another, but they're kind of unpredictable with their movements. That's because liquids can conform to the shape of a container, but not the volume. So, for instance, let's say you had a container that can hold 25 mL of liquid, but you on Lee had 10 mL of liquid. Yes, the liquid itself would conform to the shape of the container, but it wouldn't be able to fill it up because there's not enough of it. And that's what's going on with this liquid. They basically spread out as much as they can, but they can't take up the volume if there's not enough of it. Finally, gasses for gas is we can see here that the gas is these atoms over here on the right are even Mawr spread apart from one another. That's because gasses have total freedom and liberation from one another. They're moving around even mawr randomly than liquids. So we're gonna stay here. That gas is, they assume both the shape and volume of a container. So no matter how large your container gasses will spread around enough to take up every square inch off the container. Now, if we're looking at the elements of the periodic table, we can see that a vast majority of them are shaded in black and gray. so a vast majority of our elements mawr under standard room temperature and pressure will exist as a solid. We can see that when it comes to liquids, there's only really two liquids under those conditions and that be mercury and bro meat. And then when it comes to gas, is there's quite a few gas is so we have hydrogen. We have nitrogen, oxygen, flooring, chlorine. And then the last group is pretty easy to remember that there the gas is because they're called the noble gasses, right? So the name gives it away. So the name of Group eight A are the noble gasses. Now you might also notice that from our F toe o. G. They're not shaded in any color. That's because those elements majority of them have been synthesized in the lab. And because they're so loud, low down on the periodic table, their masses incredibly great, this leads to their high instability. Okay, so they're not very stable, and because of that, it's hard to really pinpoint the exact phase. They would exist under 25 degrees Celsius and one atmosphere, so as a result, we just say that they don't have a face under those temperature and pressure conditions. All right, so just remember, when it comes to our three phases of matter, what the temperature and pressure conditions that each one of these elements exist. This is key to answering certain questions when it comes to the arrangement and the presence of an element. So now that we've looked at the periodic table on its phases, let's move on to some questions.


Periodic Table: Phases (Simplified) Example 1

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So in this example question, it says, identify the element that is a representative element that is not die atomic in the second period. That assumes the shape and volume of the container that it is in. So there's a lot of information being thrown at us right now. First, we're gonna say it is a representative element. Remember, Representative Elements is just one of the large categories for the elements of the periodic table. If your representative element, that means you cannot be a transition metal. Unfortunately, all of these choices are representative elements. None of them are transition metals. So that part's not gonna help us. Well, next, it is not di atomic. Well, here, beryllium is mono atomic. Silicon is mono atomic. Boron is mono atomic, neon and argon. So that also is not gonna help us too much. Now they're getting to some important stuff. They're saying, Second period, so second period means that in the second row of the periodic table, and they say that it assumes the shape and volume of the container that it is in. So if it assumes both shape and volume, that means that it is a gas, so basically this question is asking us to find an element that's in the second row of the periodic table and is also a gas. So come up here. We're gonna say second row is here, and the only ones that are gasses are nitrogen, oxygen, flooring and neon. But out of those four neon is the only one that's given to us as a choice. So that would mean that option D would be are correct. Answer. So everything we've been learning about the periodic table, it adds, on top of one another, you got to remember, representative elements versus transition metals. You have to remember phases. Um, you have to remember elemental forms. This is the key to getting the type of question like this. Correct. So again, the only thing that fits all of these descriptions perfectly would be option. Deep neon

Which of the following elements is a nonmetal that is a polyatomic solid?


Which of the following exists as a diatomic solid at room temperature?