Answer : The molecule of ethane present in 64.28 L of ethane gas at STP is, 
molecule.
Solution :
At STP,
22.4 L volume of ethane present in 1 mole of ethane gas
64.28 L volume of ethane present in 
of ethane gas
And, as we know that
1 mole of ethane molecule contains 
molecules of ethane
2.869 moles of ethane molecule contains 
molecules of ethane
Therefore, the molecule of ethane present in 64.28 L of ethane gas at STP is, molecule.
Ionization energy generally decreases down a group because as one moves down a group, the outermost electron moves <u>further away </u>from the nucleus and it takes <u>less</u> energy to remove it.
Ionization energy, also known as ionization energy, would be the minimal amount of energy needed to free an isolated gaseous atom's or molecule's least loosely bonded electron.
First ionization energy often drops as you advance down a group on the periodic table. This occurs even though the outermost electron would be typically held less securely and can be removed with less energy since it travels farther away from the nucleus.
Therefore, Ionization energy generally decreases down a group because as one moves down a group, the outermost electron moves <u>further away </u>from the nucleus and it takes <u>less</u> energy to remove it.
To know more about Ionization energy
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Answer:
2. they are the smallest unit of matter
Noble gases are known for having a full outer shell of electrons which helium has as it has two electrons its first electron shell is completely filled
