SIZE OF ATOM
smallest particle of an element.
different ELEMENT - different size of atom.
ATOMIC SIZE, GOING DOWN THE GROUPS
(SIZE OF ATOMIC INCREASE)
The number proton increase with number of electron increase are arranged in shell. The number of shells occupied with electrons increases when down the group elements. The size of atom increase.
ATOMIC SIZE, ACROSS THE PERIODS
(SIZE OF ATOMIC DECREASE)
All atoms in same period have the same number of shell(s) occupied with electrons. The proton number in nucleus increase by one unit from element to next element across period. Positive charge in the nucleus increase causing nuclei attraction force strong. The electrons shell are pulled closer to the nucleus. The size of atom decrease.
SIZE OF ION
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| Size of positive charged ion (CATION) are smaller than their neutral atom. WHY ? Number of proton is more than number of electron in cation. The POSITIVE CHARGE of the nucleus INCREASES. The FORCE OF ATTRACTION of nucleus on the electrons INCREASES. The electrons shell are pulled closer to the nucleus. Ionic size become smaller. | | |
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Size of negative charged ion are larger than their neutral atom. By adding electron to a neutral atom, then formed ANION. Number of electron increase causes repulsions(tolakan) between electron. The force of attraction of nucleus on the electrons weaker and electron move further apart. The ionic size become larger.
