Answer:
The intermolecular forces between water molecules are stronger than those between oxygen molecules. In general, the bigger the molecule, the stronger the intermolecular forces, so the higher the melting and boiling points.
In 1869, just five years after John Newlands put forward his law of octaves, a Russian chemist called Dmitri Mendeleev published a periodic table. Mendeleev also arranged the elements known at the time in order of relative atomic mass, but he did some other things that made his table much more successful.
i hope this helps in some way!
The answer is C. No all cells have cell walls. Prokaryotes don’t have a nucleus or chloroplast. Leaving C to be correct
Explanation:
calcium ion is denoted as - Ca ²⁺
The number of electrons in a neutral atom of calcium = 20 , but since ,
it is charged atom ,
i.e. +2 , the number of electrons in calcium ion = 18 .
From , the question ,
The mass number = 41 ,
and
since ,
the mass number = number of protons + number of neutrons .
number of neutrons = mass number - number of protons
since ,
The number of protons for calcium ion = 20
number of neutrons = 41 - 20 = 21
Hence ,
number of neutrons = 21.
