Answer:
The correct option is;
D. All the elements in families 1 and 2 can place all their shell electrons in the s sub-level
Explanation:
The elements in families 1 and 2 also called the group 1A and group 2A elements are known as the alkali and alkaline earth metals. The elements in the families 1 and 2 are also referred to as the s-block elements as they have their valence electrons which are 1 and 2 respectively, in the s-orbital or s sub-level
Due to their low ionization energy, and the ease with which they donate their valence electrons, elements of the families 1 and 2 are known to be very reactive, and are found in a combined state in nature.
Answer:
There are 255, 85 grams of Strontium in 2,92 moles.
Explanation:
We perform a simple rule of three to calculate the number of grams, knowing that one mole of Sr weights 87, 62 grams:
1 mol Sr---------87, 62 grams
2,92 mol Sr-----x=(2,92 mol Sr x-87, 62 grams)/1 mol Sr= 255,8504 grams
The complete chemical reaction of aqueous Sodium sulfate and aqueous Barium nitrate is

The right side and the left side of the reaction have equal number of elements, therefore it is balanced.
Geologists have a rule of thumb: when molten rock cools and solidifies, crystals of compounds with the smallest lattice energies appear at the bottom of the mass because of high power of solubility.
<h3>What is lattice energy? </h3>
The lattice energy is defined as the energy change upon the formation of one mole of crystalline ionic compound from its same constituent ions, that are assumed to be initially in the state of gases. It is also defined as measure of the cohesive forces which bind ionic solids together.
As the lattice energy of the ionic compound increase the solubility of that particular compound decrease. Hence compound which have low lattice energy are more soluble than compound having high lattice energy. When molten rocks cools and solidified, the compound having smallest lattice energy become more soluble than crystals of compound which have large lattice energy. Therefore, crystal of compound with the smallest lattice energy start appearing at the bottom of the mass.
Thus, we concluded that due to high solubility power of compound with low lattice energy appear at the bottom of the mass.
learn more about lattice energy:
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