The elements present in periodic table generally represented as $X_{Z}^{A}$ . Here X will be the element in the periodic table, A is the atomic mass number of the element X and Z is the atomic number of the element X.

So, the number 4 is the atomic mass number of He and He-4 is the stable isotope of helium which can also be termed as alpha particle.

Mass number = number of protons + neutrons count.

Thus the number 4 denotes the Helium's atomic mass number.

6 0

3 years ago

Draw the major product that is formed when 2-butyne is treated with an excess of hydrogen gas and a platinum catalyst. draw the

trasher [3.6K]

Answer:

Addition of hydrogen in unsaturated hydrocarbons is known as Hydrogenation.

Major product that is formed when 2-butyne is treated with an excess of hydrogen gas and a platinum catalyst is an alkane of four carbon atom known as butane.

Here hydrogen gas is in excess, first but-2-ene will form from the but-2-yne then butane will form from the but-2ene.

1) $CH_3-CH\equiv CH-CH_3\overset{H_2/Pt}\rightarrow CH_3-CH=CH-CH_3$

2) $CH_3-CH=CH-CH_3\overset{H_2/Pt}\rightarrow CH_3-CH_2-CH_2-CH_3$

As shown in the image attached.

6 0

3 years ago

What is the molar mass of Fe(OH)3

aleksley [76]

The answer is 88.86 g/mol

5 0

3 years ago