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WorksheetsScience CUP
Total questions: 10
Worksheet time: 5mins
Give reasons The number of electrons of an ion differs from that of its atom.
Because the number of electrons in ion is less than or more than its number in the same atom by the number of lost or gained electrons.
Because it arises by sharing each nitrogen atom with three electrons to complete its outermost shell with 8 electrons and becomes more stable
Because sodium ion is formed when sodium atom loses one electron and changes
while covalent bond arises between two similar or different nonmetal
The number of known elements up till now is elements.
92
118
121
181
When an atom is changed into an ion, the..............
is changed.
number of protons
number of neutrons
number of electrons
mass number
A lithium atom (Li) changes into a lithium ion (Li +), which mean that it................
gains one proton.
gains one electron.
loses one proton.
loses one electron
The only nonmetal that exists in a liquid state is.....................
bromine,
chlorine.
hydrogen.
nitrogen.
The number of electrons in oxygen ion (0-2) is......................... electrons.
6
8
10
12
The number of......................... determines the type of element and its chemical activity.
electrons in the outermost energy level
levels filled with electrons
neutrons
protons
All the following are properties of inert gases except....................
they don't participate in chemical reactions.
their outermost electron shells are completely filled.
they form negative ions.
their molecules consist of one single atom.
During the formation of a sodium chloride molecule, sodium atom..........................
gains one electron from chlorine atom,
gives one electron to chlorine atom.
gains two electrons from chlorine atom.
gives two electrons to chlorine atom.
The bond in a sodium chloride molecule is ...........................bond.
single covalent
double covalent
triple covalent
ionic
