Answer:
The answer to your question is Selenium
Explanation:
The origin of the names of the elements comes from different origins
For example
Sanskrit words. 14 elements have roots from this language
Planets, 4 elements took their names from the planets.
Greek, 42 elements took their names from these languages
The name of Selenium comes from the greek that means moon.
Answer:
Mole fraction of 
= 0.58
Mole fraction of 
= 0.42
Explanation:
Let the mass of and = x g
Molar mass of = 33.035 g/mol
The formula for the calculation of moles is shown below:
Thus,
Molar mass of = 46.07 g/mol
Thus,
So, according to definition of mole fraction:
Mole fraction of = 1 - 0.58 = 0.42
The answer is 3. The releasing of energy means exothermic reaction. So the ΔH should be negative. And the greatest quantity of energy released means that the greatest number. So according to the table I, the answer is 3.
Answer:
that's because....
group 1 (e.g Na, K) those tend to lose one electron to gain noble gas electron configuration.
they can achieve that by just losing one electron from their outer shell.
as you go down the group 1, element gets bigger in size, which means there is more space between nucleus (which is in center of atom) and electron of outer shell. the more far away they are the less attraction force between them.
so its easier for potassuim to lose one electron than for lithuim.
so that means potassium will easily give up 1 electron to react with non metal or other element therefore it is more reactive than lithuim
but in case of non metal, the opposite happens but simple to understand.
as you go down the group 7 (halogen- Cl, Br, I) element will get bigger therefore force between nucleus and outer electron is getting smaller. they have to gain 1 electron in order to fill the outer shell (to gain noble gas electron configuration.)
as florine is more smaller in size than clorine it is more reactive because florine has more tendency to pull extra electron from metal or other element towards its side. so it easily gain 1 electron to react.
If you take your mom's advice, a. the room will be cooled by minimizing heat transfer by reflection.
The Sun is heating your room by its <em>radiation</em>.
The aluminium foil is shiny, so it reflects the Sun’s radiation back outside the window.
<em>Convection</em> is the transfer of heat caused by the air moving around in your room.
<em>Conduction</em> occurs only when a hot object is in contact with a cooler object.
