The primary reason for this was that Mendeleev
didn't know that atomic numbers actually existed. Atomic numbers
were only discovered a period after Mendeleev's time. The use of X-rays made it
possible to find the atomic number, and those had not been discovered yet. <span>
<span>The periodic table was then arranged in 1913 by Henry Moseley
in an arrangement according to atomic number.</span></span>
Answer:
CaCO3
Explanation:
The molecule is formed by the calcium cation Ca+2 and the carbonate anion CO3−2.
Answer:
The molar mass of the unknown gas is 
Explanation:
Let assume that the gas is O2 gas
O2 gas is to effuse through a porous barrier in time t₁ = 4.98 minutes.
Under the same conditions;
the same number of moles of an unknown gas requires time t₂ = 6.34 minutes to effuse through the same barrier.
From Graham's Law of Diffusion;
Graham's Law of Diffusion states that, at a constant temperature and pressure; the rate of diffusion of a gas is inversely proportional to the square root of its density.
i.e

where K = constant
If we compare the rate o diffusion of two gases;

Since the density of a gas d is proportional to its relative molecular mass M. Then;

Rate is the reciprocal of time ; i.e

Thus; replacing the value of R into the above previous equation;we have:

We can equally say:






Location = nucleus ,
and you can see the total charge on the number that written below the substance, which would be 28+
hope this helps
Answer:
The correct answers are:
• Softer, porous, or more permeable rocks weather faster than harder rocks.
• Rocks in warmer climates weather faster than rocks in colder climates.
• The more water present, the faster the rate of weathering.
Explanation:
Weathering is the process through which the surface minerals of rock are broken down and loosened. This occurs through the action of extreme temperatures, rainwater and biological activity.
Hope this helps- Good luck ^w