Hiranandani Foundation School International
2023-2024
SUBJECT: Science
GRADE – VIII DIV- A,B,C
STUDENT`S NAME:
TOPIC – Ionic
covalent bonds
DATE: 5th October, 2023
and WORK SHEET - 08
Formation of Ions
1. Use the words below to complete sentences a-e.
charge
anions
positively
gain
negatively
atom ionic
lose
atoms
cations
• An ion is the name for an ___________ or group of ____________ that has lost or
gained electrons and has a _____________ .
• Metal atoms ____________ electrons to form ________________ charged ions.
• Non-metal atoms ____________ electrons to form ________________ charged ions.
• Positive ions are known as ___________ and negative ions are called ____________ .
• Positive and negative ions can form a strong attraction to one another which is called
an ___________ bond
2. Complete the table to show what happens when these atoms form ions.
Number of electrons
Atomic
symbol
Electron
config.
Li
2.1
Na
2.8.1
K
2.8.8.1
Mg
2.8.2
Ca
2.8.8.2
Metal or
non-metal?
In the
atom?
Lost or gained?
How many?
In the
ion?
Formula
of ion
O
2.6
S
2.8.6
F
2.7
Cl
2.8.7
3. Complete the diagrams to what happens to the electrons in magnesium and oxygen
atoms when they react with each other. Repeat this for potassium and fluorine atoms.
✓ Draw dots for electrons in the metal atoms
✓ Draw crosses for electrons in the non-metal atoms
✓ If an electron is transferred from atom to another, draw the electron in the new
location as it was (i.e., dot or cross) in the original atom.
Atom: Mg
Atom: O
Atom: K
Atom: F
Ion: Mg2+
Ion: O2-
Ion: K+
Ion: F-
4. The image below represents a specific type of ion.
137
56
Ba
2+
Explain what each piece of information (i-iv) tells you about the ion. In your answers
include details about the number of protons, neutrons and electrons in this ion.
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5. What is a simple molecule?
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6. What type of bonding holds atoms in a simple molecule together?
………………………………………………………………………………………………………………………………………
7. Give three examples of simple molecular substances
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8. Simple molecular substances have low melting points. Explain why.
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9. Diamond has a high melting point. Explain why.
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10.Which statement(s) below describe(s) the structure of graphite?
• Each carbon atom is covalently bonded to four other atoms.
• The layers are held together by weak intermolecular forces.
• Electrons not involved in covalent bonding are delocalised.
• The structure is very hard.
11.What properties does graphite have that are unusual for a non-metal?
………………………………………………………………………………………………………………………………………
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12.Diamonds can be used as cutting tools. What property of diamond makes it suitable for
use as a cutting tool?
………………………………………………………………………………………………………………………………………
13.Graphite can be used as a lubricant. What property of graphite makes it suitable for use
as a lubricant?
………………………………………………………………………………………………………………………………………
14. The table below shows the melting points of graphite, oxygen and diamond (under
certain conditions), and whether they conduct electricity or not.
•
•
•
•
•
• Which substance (A, B or C) is graphite?
Substance:____
• Which substance (A, B or C) is oxygen?
Substance:____
• Which substance (A, B or C) is diamond?
Substance:____