The answer is high melting and boiling points. Because alkali metals have a range of melting points from a high of 179 °C (354 °F) for lithium to a low of 28.5 °C (83.3 °F) for cesium
<h2>Hardness, lustre, and colour.</h2>
Explanation:
These Rocks shown in photographs are made of different types of minerals which have properties as follows:
●The color of the rock is grey, brown and yellow after it is ground into a powder its color is streak.
● The lustre of the rock tells how shiny the rocks are.
● Other properties include hardness, texture, shape, and size.
Answer:
moles of ammonia produced = 0.28 moles
Explanation:
The reaction is

As per equation, one mole of nitrogen will react with three moles of hydrogen to give two moles of ammonia
So 0.140 moles of nitrogen will react with = 3 X 0.140 moles of Hydrogen
= 0.42 moles of hydrogen molecule.
this will give 2 X 0.140 moles of ammonia = 0.28 moles of ammonia
the moles of ammonia produced = 0.28 moles
Here the nitrogen is limiting reagent.
They are called ISOTOPES.
:)
About 1 gram. 1 part of 50 is 2%