Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney. Hanley Rd, Suite St. Louis, MO Subject optional. Email address: Your name:. Example Question 1 : Understand Basic Chemistry.
Which of the following defines the identity of an element? Possible Answers: Number of neutrons. Correct answer: Number of protons. Explanation : The identity of an element is determined by the number of protons. Report an Error. Example Question 2 : Identifying Elements.
What element could contain seven protons, eight neutrons, and seven electrons? Possible Answers: Carbon. Depending on isotope and ionization, any of these could have the given configuration. Correct answer: Nitrogen. Explanation : An element is defined by its number of protons. Example Question 1 : Identifying Elements. Which of the following molecules consists of only one element? Possible Answers:.
Correct answer:. Explanation : Elements are shown on the periodic table. Is it possible to form a compound from only one element? Possible Answers: Yes; compounds and elements are synonyms. Yes; diatomic gases are compounds that consist of only one element. Yes; water is a compound that consists of only one element.
Correct answer: Yes; diatomic gases are compounds that consist of only one element. Explanation : Elements are defined by the number of protons in a given atom, and the atom is the smallest unit of an element.
Example Question 5 : Identifying Elements. Which of the following atomic properties, if known, will reveal the identity of the element? Possible Answers: More than one of these answers could allow us to identify the given atom. Correct answer: The number of protons. Explanation : There are two properties that can be used to identify an element: the atomic number or the number of protons in an atom. Example Question 6 : Identifying Elements.
Which of the following phase labels are used for all diatomic elements? Possible Answers: r. Correct answer: g. Explanation : Diatomic elements are commonly referred to as diatomic gases because whenever they are by themselves, they bond to themselves that is where the "2" subscript comes from.
Example Question 7 : Identifying Elements. Possible Answers: P. And this is in its graphite form. This right here is lead. This right here is gold. And all of the ones that I've shown pictures of, here-- and I got them all from this website, right over there-- all of these are in their solid form.
But we also know that it looks like there's certain types of air, and certain types of air particles. And depending on what type of air particles you're looking at, whether it is carbon or oxygen or nitrogen, that seems to have different types of properties.
Or there are other things that can be liquid. Or even if you raise the temperature high enough on these things. You could, if you raise the temperature high enough on gold or lead, you could get a liquid. Or if you, kind of, if you burn this carbon, you can get it to a gaseous state. You can release it into the atmosphere.
You can break its structure. So these are things that we've all, kind of, that humanity has observed for thousands of years. But it leads to a natural question that used to be a philosophical question. But now we can answer it a little bit better. And that question is, if you keep breaking down this carbon, into smaller and smaller chunks, is there some smallest chunk, some smallest unit, of this stuff, of this substance, that still has the properties of carbon?
And if you were to, somehow, break that even further, somehow, you would lose the properties of the carbon. And the answer is, there is. And so just to get our terminology, we call these different substances-- these pure substances that have these specific properties at certain temperatures and react in certain ways-- we call them elements. Carbon is an element. Lead is an element. Gold is an element. You might say that water is an element. And in history, people have referred to water as an element.
But now we know that water is made up of more basic elements. It's made of oxygen and of hydrogen. And all of our elements are listed here in the Periodic Table of Elements. C stands for carbon-- I'm just going through the ones that are very relevant to humanity, but over time, you'll probably familiarize yourself with all of these. This is oxygen. This is nitrogen. This is silicon. Au is gold. This is lead. And that most basic unit, of any of these elements, is the atom.
So if you were to keep digging in, and keep taking smaller and smaller chunks of this, eventually, you would get to a carbon atom. Do the same thing over here, eventually you would get to a gold atom. You did the same thing over here, eventually, you would get some-- this little, small, for lack of a better word, particle, that you would call a lead atom.
And you wouldn't be able to break that down anymore and still call that lead, for it to still have the properties of lead. And just to give you an idea-- this is really something that I have trouble imagining-- is that atoms are unbelievably small, really unimaginably small. So for example, carbon. My hair is also made out of carbon.
In fact, most of me is made out of carbon. In fact, most of all living things are made out of carbon. And so if you took my hair-- and so my hair is carbon, my hair is mostly carbon.
So if you took my hair-- right over here, my hair isn't yellow, but it contrasts nicely with the black. My hair is black, but if I did that, you wouldn't be able to see it on the screen.
But if you took my hair, here, and I were to ask you, how many carbon atoms wide is my hair? So, if you took a cross section of my hair, not the length, the width of my hair, and said, how many carbon atoms wide is that? And you might guess, oh, you know, Sal already told me they're very small. So maybe there's 1, carbon atoms there, or 10,, or , I would say, no.
There are 1 million carbon atoms, or you could string 1 million carbon atoms across the width of the average human hair. That's obviously an approximation. It's not exactly 1 million. But that gives you a sense of how small an atom is. You know, pluck a hair out of your head, and just imagine putting a million things next to each other, across the hair. Not the length of the hair, the width of the hair. It's even hard to see the width of a hair, and there would be a million carbon atoms, just going along it.
An atom can gain or lose neutrons and still be the same element. Method 2. The total electron count equals the atomic number. In a neutral atom, the number of electrons is exactly equal to the number of protons. This number is the atomic number of the element, which you can look up on the periodic table.
If you are a little further in your chemistry studies, you might be given an electron configuration to read. All of the superscript numbers like this are electron counts, so add all these together to find the total number of electrons.
This is carbon, with atomic number 6. Note that this only holds true when the atoms are in electrically neutral states, not ionized. But unless specified otherwise, this is the state we talk about when we discuss element characteristics. Method 3. Memorize the periodic table structure to read electron configurations quickly.
The structure of the periodic table is closely related to how electron orbitals are filled. With a little practice you can jump directly to the right region of the periodic table. The first row hydrogen and helium fills up the 1s orbital from left to right.
Think of these, plus all elements in the first two columns, as the "s-block". Each row of the "s-block" fills up one s orbital. The right-hand side of the table is the "p-block", starting with boron through neon. Each row of the "p-block" fills up one p orbital starting with 2p. The transition metals in the center form the "d-block". Each row fills up one d orbital, starting with scandium through zinc filling 3d. The lanthanides and actinides at the bottom of the table fill the 4f and 5f orbitals.
Some elements here break the pattern, so double-check these. Go to the "p-block" on the right, and count rows down from 2p boron until you reach 5p indium. Since this element has two electrons in 5p, count two elements into this row of the p-block to get the answer: tin. Method 4. Compare the spectra to the known spectra of elements. In spectroscopy, scientists examine how light interacts with an unknown material.
Each element releases a unique pattern of light, which you can see on the spectroscopy results, called "spectra". If your spectrum has all those same lines on it, the light came from the element lithium.
Want to know why this works? Electrons only absorb and emit light at very specific wavelengths meaning specific colors.
0コメント