Answer: hey so I’m taking the same test as you right now. I’m on that question and I searched it up and came on here. Would you mind telling me the answer?
Explanation:
Answer:
About 60.
Explanation:
Mendeleev knew of 63 elements. He wrote their properties on cards and arranged them in order of atomic mass.
That's how he discovered that the properties of elements are periodic functions of their atomic masses.
Answer:
Average speed of helium is higher than argon.
Explanation:
The average speed of helium is higher than argon atom under the conditions specified because of lower mass of the helium atom as compared to argon atom. Average speed of an atom is inversely proportional to mass of the atom. If mass of an atom decreases, the atom moves with higher speed while on the other hand, if the mass of an atom increases the average speed of an atom decreases.
