An atomic mass unit is defined as precisely 1/12 the mass of an atom of carbon-12.
I don't know which one I should answer
Some material from meteors lingers in the mesosphere, causing this layer to have a relatively high concentration of iron and other metal atoms. Very strange, high altitude clouds called "noctilucent clouds" or "polar mesospheric clouds" sometime form in the mesosphere near the poles.
I really hope this helps! I wish you the best of luck!
Solubility data of a certain solute with a certain solvent is empirical. There are constant values for this at varying temperatures. For KCl in water at 25°C, the solubility is 35.7 g/100 mL of water. When you compare this with the solubility data of KCl with ethanol, this means that KCl is more soluble in water than in ethanol. This is true because KCl is an ionic salt which is very soluble in water.
Valence électrons don’t define which group You are in so you can cross those choices out.
A would be incorrect because element 1 has 1 valence electron while element 2 has 2 valence electrons.
D would be correct because both elements have two valence electrons.
Also, pls don’t hate if I am wrong!
