Suppose you have one container of nitrogen gas (molar mass: 28.0 g/mol) and one container of helium gas (molar mass: 4.00 g/mol). They are separated from each other by a valve that keeps them both from mixing (until
the valve is opened and they mix). Both containers are at 400.0 K. The container of nitrogen Aas is at 400.0 K, and so is the container of helium
gas.
The nitrogen gas container has a pressure of 5.00 atm and a volume of 2.00 L, and the helium gas container has a pressure of 9.00 atm and a
volume of 3.00 L. There are 0.305
mol of nitrogen and 0.823 mol of helium. After the valve is opened, the gases mix and each gas fills the volume of
both containers. What is the partial pressure of the helium gas after this gas mixing? You can assume that the temperature after the mixing is also
400.0 K
Less than 2.00 atm.
Between 2.00 atm and 4.00 atm.
Between 4.00 atm and 6.00 atm.
Between 6.00 atm and 8.00 atm.
More than 8.00 atm.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.

your answer would be “dry”