- Group 1 Elements (Alkali Metals):
- These are elements in the first column of the periodic table, including Lithium (Li), Sodium (Na), Potassium (K), and so on.
- They have 1 electron in their outermost electron shell.
- To achieve a full outer shell (similar to noble gases), they prefer to lose this single electron.
- Group 7 Elements (Halogens):
- These are elements in the second to last column of the periodic table, including Fluorine (F), Chlorine (Cl), Bromine (Br), and so on.
- They have 7 electrons in their outermost electron shell.
- To achieve a full outer shell, they prefer to gain 1 electron.
- Predicted Bonding:
- Given that the Group 1 element (X) wants to lose an electron and the Group 7 element (Y) wants to gain an electron, they will transfer electrons between them.
- X will give its 1 electron to Y. This results in X becoming a positively charged ion (cation) and Y becoming a negatively charged ion (anion).
- The bond formed due to the attraction between these oppositely charged ions is called an ionic bond.
- Predicted Formula:
- As the Group 1 element loses 1 electron and the Group 7 element gains 1 electron, their bonding ratio is 1:1.
- This means the most likely formula for their compound is XY.
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Hey Ari, That’s where I’m confused. Isn’t halogens in group 17? But here it is group 7. How can I identify the bonds in such case?
hey some textbooks only use the first 3 periods of the table and name the groups 1-8
for period 4 and beyond (and for the whole table in general) we say groups 1-18
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got it ! Thank you so much. 
Hey Elvina! It’s just different conventions, 7=17
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