What does the period number in the periodic table designate?

Answer 1

Answer

The period number tells you how many protons, electrons and nuetrons exist in that element as a single atom. It doesn't tell you how it exists in nature. For example, Oxygen, which is 8, has that number of protons, electrons and nuetrons. But it won't occur in nature that way. The only elements that occur naturally are the Noble gases, the very last column all the way to the right. All the other elements will occur as ions in compounds or in molecules.

8 is the number for oxygen, then there are 8 protons, 8 nuetrons and 8 electrons. Oxygen will always have 8 protons and 8 nuetrons. When it forms compounds or molecules with other elements, it will give up electrons to the elements or gain electrons from the other elements. It is the number of nuetrons that make an element that particular element. That number will not change. Only the number of electrons will change.

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EDIT: ALMOST EVERY SINGLE SENTENCE IN THE ABOVE ANSWER IS INCORRECT. I AM A CHEMISTRY PROFESSOR AT A TOP-10 UNIVERSITY IN THE UK. PLEASE DO NOT USE THIS AS AN ACCURATE REFERENCE FOR AN EXPLANATION OF PERIOD OR ATOMIC NUMBER.

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INACCURACIES IN THE ABOVE ANSWER:

- "The period number tells you how many protons, electrons and nuetrons exist in that element as a single atom." THIS IS SIMPLY NOT THE CASE. THE QUESTION IS ABOUT THE "PERIOD NUMBER", NOT THE ATOMIC NUMBER. EVEN IF IT WERE, THIS IS AN INACCURATE DESCRIPTION OF ATOMIC NUMBER.

- "It doesn't tell you how it exists in nature." THIS STATEMENT IS ACCURATE.

- "... has that number of protons, electrons and nuetrons." NO, IT DOESN'T ALWAYS. THE ONLY NUMBER WHICH IS ALWAYS 8 IS THE NUMBER OF PROTONS.

- "The only elements that occur naturally are the Noble gases". THIS IS NOT TRUE.

- "All the other elements will occur as ions in compounds or in molecules." THIS IS NOT TRUE EITHER - ELEMENTS CAN OCCUR AS COVALENTLY BONDED MOLECULES, HYDROGEN-BONDED MOLECULES, ETC ETC.

- "...nuertrons..." NEUTRONS IS SPELT EU, NOT UE.

- "Oxygen will always have 16 protons and 16 nuetrons." AGAIN, SIMPLY NOT THE CASE. ISOTOPES HAVE DIFFERENT NUMBERS OF NEURTRONS. FOR EXAMPLE, OXYGEN CAN EXIST WITH 8 NEUTRONS, 9 NEUTRONS AND 10 NEUTRONS.

- "It is the number of nuetrons that make an element that particular element. That number will not change. Only the number of electrons will change.". THIS IS INACCURATE. IT IS THE NUMBER OF PROTONS WHICH DEFINES AN ELEMENT. SEE ABOVE.

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THIS IS A PERFECT EXAMPLE OF MISINFORMATION, THE LIKE OF WHICH MAKES THE internet A WORRYINGLY USELESS, UNRELIABLE AND EVEN DANGEROUS PLACE.

ADMITTEDLY, THIS IS AN UNBELIEVABLY BAD EXAMPLE OF MISINFORMATION, CONTAINING A LARGE AMOUNT OF ALMOST EXCLUSIVELY INACCURATE STATEMENTS.

YOU ONLY HAVE TO READ THE HOMEPAGE OF THE ABOVE AUTHOR TO REALISE THAT IT IS HIGHLY UNLIKELY THAT ANYTHING FROM THIS CONTRIBUTER WILL HAVE ANY BASIS IN SCIENCE OR REALITY: " After having my own landscape design business for 5 years, I went back to school last year to study landscape architecture. ... I'm suprised to find that I actually seem to know the answers to some people questions.". IT IS ASTOUNDING THAT SOMEONE WITH THIS BACKGROUND CAN HAVE THE AUDACITY, ARROGANCE AND PURE IDIOCY TO ATTEMPT TO ANSWER A QUESTION OF THIS NATURE.

PLEASE COULD I ASK THE AUTHOR OF THE ABOVE ANSWER TO CORRECT ALL THE INACCURACIES IN THIS ANSWER, PERHAPS BY CONSULTING A BASIC CHEMISTRY BOOK RATHER THAN HEARSAY AND INACCURATE RECOLLECTIONS OF AGE-OLD LEARNINGS. IT MAY BE BENEFICIAL FOR THIS AUTHOR TO COMPLETELY REMOVE HER ANSWER ALTOGETHER.

FOR ALL YOU BUDDING CHEMISTS OUT THERE WHO ARE TRYING TO FIND OUT AN ACCURATE ANSWER TO THE ABOVE QUESTION, PLEASE, PLEASE IGNORE THIS ONE AND TAKE A LOOK AT A BASIC SCHOOL TEXT BOOK. GOOD LUCK TO YOU!

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(applause) go professor! You tell him (or her)...

woooooo :D

Answer 2

the numbe of electrons shells