The elements whose electron configurations end with f electrons are in the Lanthanide and Actinide series: those long series at the bottom of the Periodic Table (see image).
The atoms are adding electrons into f orbitals, but the f electrons are not always the last electrons in the electron configuration.
For example, the electron configuration of Eu is [Xe]6s²4f⁷, but that of Gd
is [Xe] 6s²4f⁷5d.
I have blocked off in <em>red</em> all the <em>exceptions</em> like Gd.
Answer:
The strongest gravitational attraction between the two objects will be experienced when the distance between the two objects is smallest.
Explanation:
According to Newton's law of universal gravitation, the force of attraction between two objects is proportional to the products of their masses and inversely proportional to the square of the distance of separation between the two objects. This attraction between objects is known as gravity and it applies to all objects in the universe.
From the law of universal gravitation, since their is an inverse square relationship between gravitational force and the distance of separation between two interacting objects, an increase in the distance of separation will result in weaker gravitational forces. For example, if the distance of separation between two objects is increased by a factor of 2, then the force of gravitational attraction is decreased by a factor of 4 (since 2² = 4). However, if the distance of separation between the two objects is decreased by a factor of two, i.e. is halved, then the force of gravitational attraction is increased by a factor of 4.
Thus, the strongest gravitational attraction between the two objects will be experienced when the distance between the two objects is smallest.
Answer:
1.02 moles of AlCl3
Explanation:
Consider the balanced reaction equation shown below;
2Al(s) + 3CuCl2(aq) -------> 2AlCl3 (aq) + 3Cu(s)
This is the balanced reaction equation for the reaction going on above. Recall that the first step in solving any problem is to accurately put down the chemical reaction equation. This balanced reaction equation always serves a reliable guide in solving the problem at hand.
Given that;
3 moles of CuCl2 yields 2 moles of AlCl3
1.53 moles of CuCl2 yields 1.53 × 2 / 3 =1.02 moles of AlCl3
Answer: The equilibrium concentration of hydrogen gas is 0.0269 M
Explanation:
The chemical reaction follows the equation:
At t = 0 0.044M 0.044M 0.177M
At (0.044-x)M (0.044-x)M (0.177+x)M
The expression for for the given reaction follows:
We are given:
Putting values in above equation, we get:
Hence, the equilibrium concentration of hydrogen gas is (0.044-x) M =(0.044-0.0171) M= 0.0269 M