Today, we are going to continue where we left off in Day 4 of “O Levels Chemistry Tips Blog Marathon” on the topic of Atomic Structure.
We shall discuss on the formation of ions from the atoms present in the periodic table.
FORMATION OF IONS:
If an atom gains electrons, it becomes a Negative Ion (Anion). The number of electrons is greater than the number of protons.
Example, the fluoride ion, F- is formed by adding 1 electron to an fluorine atom.
If an atom loses electrons, it becomes a Positive Ion (Cation). The number of electrons is less than the number of protons.
Example, the sodium ion, Na+, is formed by removing 1 electron from a sodium atom.
Do note that the number of electrons gained or lost corresponds to the Charge of the Ion.
Atoms form ions because their ions have the electronic structure of Noble Gases (Group 0 of Periodic Table).
Positive ions are formed by atoms with 1-3 electrons in their valence shells, which they lose to form Positive ions with Noble Gas Structures. Thus, METALS –> POSITIVE IONS
Negative ions are formed by atoms which require an extra 1 or 2 electrons added to their outermost shells to attain a Noble Gas Structures. Thus, NON-METALS –> NEGATIVE IONS
In the formation of ions, the number of electrons changed only. Protons and Neutrons are located in the Nucleus and are not involved in the formation of ions.
We have gone through the theory, now let’s check out a few O Level Chemistry – type questions related to this topic.
Question 1: Based on Topic “Atomic Structure”
An atom has an atomic number of 20. What is the electronic arrangement of this atom?
A. 20
B. 2.18
C. 2.8.10
D. 2.8.8.2
and
Question 2: Based on Topic “Atomic Structure”
The information below shows some information about 2 ions, X and Y.
Protons Neutrons Electrons
X 19 20 18
Y 21 25 18What are X and Y?
A. Positive ions of different elements
B. Positive ions of the same element
C. Negative ions of the same element
D. Negative ions of different elements
“Winners don’t do different things; They do things differently”
The best way to learn is through participation, and the ability to determine what is right and wrong, and make improvements to it.
PS: Leave your answers and reasonings in the “Leave A Reply” section below.
PPS: We will come in to give our suggested answers and though-process very soon.
ANS OF FIRST IS “D” BECAUSE first shell can have only 2 electrons in it and second
can have 8 and third have 8 and the rest will got the next shell
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question 1 answer is d.but can it be a?abd question 2 answer is A.
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QUANSAH ALBERT Reply:
May 2nd, 2009 at 11:50 pm
1.the answer is D.This is because the K-Shell takes a maximum of 2 electrons.L-Shell 8,M-Shell 8 and the last shell N takes the 2.
2.The answer is A.Since X and Y have different proton numbers which exceeds their electrons the answer chosen is valid.
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ans of 1 is C and 2 is A
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1 ans is d
2 ans is a
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1ans is d
2 ans is a
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