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CHEMISTRY FORM 2


1. STRUCTURE OF THE ATOM, AND THE PERIODIC TABLE
2. CHEMICAL FAMILIES AND PATTERNS IN PROPERTIES
3. CHEMICAL BONDING AND STRUCTURE
4. SALTS
5. EFFECT OF AN ELECTRIC CURRENT ON SUBSTANCES
6. CARBON AND SOME OF ITS COMPOUNDS
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Chemical Bonding and Structure: Types of bond across a period

3.0 Chemical Bonding and Structure


3.9 Types of bond across a period


As seen previously, the ability to lose or gain electrons varies across each period of the Periodic Table. Study the trends in Period 3 elements represented in Figure 3.9 then answer Questions 3.9.


Bond types across periods, high school chemistry

Figure 3.9: Bond types across periods


Questions 3.9

  1. Which elements give up electrons and therefore form ionic and metallic bonds? When do they form each type of bond?
  2. Identify the elements which form ionic and covalent bonds. When do they form each type of bond?
  3. Name the element that forms covalent bonds only, no matter what it combines with? Explain your answer.
  4. Which metal is expected to show a bond type similar to that of the element named in Question 3?

Answers to Questions 3.9


Across each period, bond type within elements is metallic from Group I to III. But this changes to covalent from Group IV to VII. For compounds, bond type is ionic from Group I to III when combined with non-metals (Group IV to VII). This changes to covalent from Group V to VII if the compound is of non-metals only.


Aluminium compounds, such as aluminium chloride (AlCl3), show some covalent properties. This is because losing all the three outer electrons requires so much energy; so aluminium tends to share rather than totally lose electrons. That is, ionic character decreases from Group I to III.