30. Which two notations represent atoms that are isotopes of the same element?
A) 31 Sn and 30°Sn
B) 581 Sn and 13 Sn
C) 3°O and LOF
D) 19 Cl and 18K

581 Sn and 13 Sn

Explanation:

581 Sn and 13 Sn are both Sn which are the same element with different masses. Isotopes are same element with different masses and the elements can have different masses because of different number of neurons

1. 1 mole of anything contains 6.022x10^23 pieces  

d  

2. a  

3. c, number  

5. 1.24x10^24atoms / 6.022x10^23atoms/mole = 2moles h2 atoms  

6. fe2br3 mass = 2moles x mass fe + 3 moles x mass br  

molar mass = grams / number of moles = g/mole  

to find moles = g / molar mass  

to find mass = g = molar mass / moles

answer: lol

explanation:

lol