Hello Shreya,

Aluminum (Al), cobalt (Co), sodium (Na), selenium (Se), and silicon (Si) are considered beneficial elements for plants.

Sodium can stimulate plant growth, Silicon plays an important role in cell wall stability by bridging between polyuronides and stimulating lignin synthesis. Selenium is essential for animals; Se fertilization may be beneficial for human and animal health in areas with Se-deficient soils. Alluminium may may alleviate proton toxicity and increase the activity of antioxidant enzymes.

That's why they are known as beneficial elements.

hope this helps

hello!

These elements are not essential but their presence promotes the growth specially in some plants.

example of these elements are venedium,selenium,silicon,aluminium,sodium,titanium.

I hope your doubt has been cleared now.thank you