priekaparki

How does density of an element correlate to atomic size down a group on the periodic table?

Can someone please help me ? I am struggling with this. Thanks to all. All help is grealty appreciated.

Okay, as you move down a group on the periodic table, the atomic radius (basically the same as atomic size) increases due to more mass and volume of the element. As you move down a group, there will be more protons and neutrons in the nucleus, and additional electron clouds will be added. This relates to density of an atom because of the additional electrons shielding the valence electron from the positively charged nucleus core. For example, if you have an element in group 2, meaning there are 2 electrons in the valence shell, it depends on how down the element is in the group for the atomic size and density to be determined. The farther down the element is, the more neutrons and protons there are, meaning the atomic size increases. However, because there are more electron clouds picked up, the 2 valence electrons the element has (which it always has, as long as it exists in group 2) feel less of a pull to the nucleus, because of more shielding electrons in between the valence electrons and the positive nucleus. Because there is less pull of the valence electrons felt, the entire atom expands outward (decreasing the density)

To sum up, although the atomic size of an element increases farther down a group of the periodic table, the density decreases due to the atom expanding outward, less inward pull.

What is the identity element for addition?
0
1
-1
There is no identity element for addition

and what IS a identity element??
Thank you!
Thank you everybody! lots of help!

The identity element is 0.

In short, the identity is the number that gives you back the original number. The addition identity is 0, since x + 0 = x.

To take this a step further, the multiplication identity is 1, since 1 * x = x.

Since you’re dealing with the identity element, you’ll soon learn about the inverse. The inverse is the number that gives you the identity. For example, x + (-x) = 0, which is the addition identity. And x * (1/x) = 1, which is the multiplication identity.

Hope that helps with the identity.

Suppose you have a sample element.

How is the mass in grams of the element converted to number of atoms?

Take the grams of element and determine the number of moles this is. To do that, simply divide the number of grams you have by the elements atomic weight. Then take that answer and multiply it by Avogardro’s number.

Moles = grams / atomic weight

atoms = moles X Avogado’s Number

Write down the units (ie: g) for each step, and you will notice how the units will cancel out and leave atoms. This is a very important skill to learn, especially in chemistry. Units cancel, just like numbers can be cancelled. Learn how to do this!

2.) In the periodic table, elements of Group 1 are called?
3.) Elements of Group 2 are called?
4.) Elements of Group 3-12 are called?
5.) Group 17 elements are called?
6.) The msot active element in Group 17 is?

1. metalloid
2. alkali metals
3. alkali earth metals
4. transition metals
5. nonmetals
6. flourine

I have a project due Monday for Chemistry and I’m having a hard time determining the density of this unknown element. How would I find the density if the last known element of the halogen group is Astatine?

look it up on yahoo answers

I have a project due Monday for Chemistry and I’m having a hard time determining the density of this unknown element. How would I find the density if the last known element of the halogen group is Astatine?

look it up on yahoo answers

I’ve got an older range, Frigidaire Electri_Clean , that apparently needs a new bottom heating element. None of the parts websites have my model number (REG36HL*2). I’d guess its probably 30 years old. Are the heating elements of this vintage pretty much the same or does it have to be an exact replacement? Thanks!

Hi, they are not hard to replace, make sure that the power is off. Take your racks out (gives you more room to work), where the element goes through the back of the oven, there will be a screw on each side that holds the element brackets in place. Remove the screws and carefully pull the element towards you. Being that old you will probably find that the wires are screwed to the ends of the element. Remove those screws, be care full and find something to hold the wires from falling back through the holes, if they do your in for a lot more work then you need to. Once you have the element out, you can take it with you to your local appliance parts store. I’m not finding your model # either and I service them. Double check your number. But anyway, if you can’t find the model # they can match it up by measuring it. Chromalox, and Rapro make universal elements to replace just about anything out there.
Good luck and hope this helps

I’ve got an older range, Frigidaire Electri_Clean , that apparently needs a new bottom heating element. None of the parts websites have my model number (REG36HL*2). I’d guess its probably 30 years old. Are the heating elements of this vintage pretty much the same or does it have to be an exact replacement? Thanks!

Hi, they are not hard to replace, make sure that the power is off. Take your racks out (gives you more room to work), where the element goes through the back of the oven, there will be a screw on each side that holds the element brackets in place. Remove the screws and carefully pull the element towards you. Being that old you will probably find that the wires are screwed to the ends of the element. Remove those screws, be care full and find something to hold the wires from falling back through the holes, if they do your in for a lot more work then you need to. Once you have the element out, you can take it with you to your local appliance parts store. I’m not finding your model # either and I service them. Double check your number. But anyway, if you can’t find the model # they can match it up by measuring it. Chromalox, and Rapro make universal elements to replace just about anything out there.
Good luck and hope this helps

I just had an oven fire. The coil element started sparking and we turned off the circuit breaker to finally stop it. There was no food burning on top of it, it’s the coil itself that burned and the outer layer has partially disintegrated. What kind of malfunction would cause this? The oven is a top quality brand about 10 years old.

if there are any chips or rust on the metal of the coil it can erode or change the composition of the flame retardant of that coil

instead of the coil getting hot, it bursts into flames.

I just had an oven fire. The coil element started sparking and we turned off the circuit breaker to finally stop it. There was no food burning on top of it, it’s the coil itself that burned and the outer layer has partially disintegrated. What kind of malfunction would cause this? The oven is a top quality brand about 10 years old.

if there are any chips or rust on the metal of the coil it can erode or change the composition of the flame retardant of that coil

instead of the coil getting hot, it bursts into flames.