alternately - alternatively
You use alternately to say that two actions or processes keep happening regularly after each other.
Each piece of material is washed alternately in soft water and coconut oil.
She became alternately angry and calm.
You use alternatively to give a different explanation from one that has just been mentioned, or to suggest a different course of action.
It is on sale there now for just £9.97. Alternatively, you can buy the album by mail order for just £10.
Alternatively, you can use household bleach.