- Elements from the same group in the periodic table are chemically reactive in a similar way
- Elements are all from the first group of the periodic table
- So, elements from the first group are chemically reactive in a similar way

- Elements from the first group are chemically reactive in a similar way
- If the elements have similar chemical reactivity , then the elements will react with other elements in a similar way
- Hence, elements from the first group will react with other elements in a similar way

- Elements from the first group will react with other elements in a similar way
- Oxygen is a kind of element
- So, elements from the first group will react with oxygen in a similar way

Hence, elements from the first group will react with oxygen in a similar way
Question: Which of these is one similarity of the elements in the first group of the periodic table?
Context: - Elements from the same group in the periodic table are chemically reactive in a similar way 
- Elements are all from the first group of the periodic table 
- Oxygen is a kind of element 
- If the elements have similar chemical reactivity , then the elements will react with other elements in a similar way