# Calculate the atomic mass of an element using the EOH hydroxide formula if the mass fraction of the element

**Calculate the atomic mass of an element using the EOH hydroxide formula if the mass fraction of the element in it is 0.575. What group is the item in?**

It is known that the mass fraction of the element is 0.575, from this, we calculate the mass fraction of the OH group, which is calculated as follows:

EON = 1

So from one we subtract the mass fraction of the element and we get the following solution:

1 – 0.575 = 0.425

Mr (OH) = 17, so we calculate the atomic mass of the element as follows:

make up the following proportion:

17 – 0.425

x – 0.575

Next, we calculate the unknown value of the number x, for this we multiply 17 by 0.575 and divide by 0.425, we get the following solution:

x = 17 × 0.575 / 0.425 = 23

This means that the atomic mass of the element is 23, which means it is sodium Na. This Element is in the I group, the main subgroup.