A few days ago
Pastinie

Periodic table?

i was asked this question is class and i really dont get it can u help me answer it?

it is:How many elements are there in the four rows int he periodic table? explain why the numbers change!

i just dont get it please answer me and the question i was asked!

Top 5 Answers
A few days ago
Smumph45

Favorite Answer

just count all the elments in the first four periods. which numbers? the atomic number varies from element to element. all different elements have a different atomic number. the atomic number is most likely to be the lowest one, apart from hydrogen, it is just one. the atomic number is the same as the proton number, and electron number. the mass no. is theno. of protons and neutrons, but i think it is in relative atomic masss, which is an average of what percentage of what isotope there is.
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A few days ago
Richard W
ok, the periodic table is divided into 4 sections, each section being a different width.

The first (with H and He at the top) is known as the ‘s’ block, the second (with B to Ne at the top) is known as the ‘p’ block, the third (the transition metals, in the middle) are known as the ‘d’ block, and the lanthanide and actinide series are known as the ‘f’ block.

To simplify things, imagine the nucleus as the sun, and then the electrons orbiting around it. The blocks refer to the orbit ‘shape’ (a simplification, but it will do), and the number of electrons that can fit in the orbit depends on the block (‘s’ orbits can hold 2 electrons, ‘p’ can hold 6, ‘d’ can hold 10 and ‘f’ can hold 14).

As you work your way along the rows of the periodic table, the number of electrons ( the atomic number) increases by one, so H has 1 electron, He has 2 etc…

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A few days ago
biscuit
the #s are the atomic numbers, meaning the # of protons (positively charged particles) in the nucleus. every time an element adds another proton in the nucleus, the atomic # changes, thus changing the element. and remember, # of protons and # of electrons (in outer shells) are equal.

if you look “periodic table” up on wikipedia, its all spelled out for you. good luck.

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A few days ago
Part Time Cynic
I agree with biscuit. Wiki’s periodic table has a link for each element too. it’s wicked! 🙂
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A few days ago
tony’s girl
that would depend on what section wouldnt it??

and although i dont feel as if i should help you…ill do it anyway…the numbers increase with the incresaing mumber of electrons in each molecule

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