Answer:
Mendeleev had left the noble gases out of his periodic table.
Explanation:
Mendeleev's periodic table is pictured in the image attached to the question.
Mendeleev's table obviously lacked the noble gases. The reason for this grave omission is simple; the noble gases were not known as at the time when he formulated his periodic table. There weren't any known elements whose properties were similar to the properties of the noble gases. This would have lead him to suspect their existence.
Answer:
PROTON AND NEUTRON
Explanation:
- The mass of proton is :
A proton is one of the main particles that make up the atom . The other two particles are neutron and electron. Protons are found in the nucleus of the atom.This is a tiny , dense region at the centre of the atom. Protons have a positive charge of one (+1) and a mass of 1 atomic mass unit ( amu ) , which is about . Together with neutrons , they make up virtually all of the mass of an atom.
- The mass of neutron is also approximately: but a little more than that .
Atoms of all elements - except Hydrogen , have neutrons in their nucleus . Unlike protons and electrons , these have no charge - they are electrically neutral . The mass of a neutron is slightly greater than the mass of a proton but not very significant
D, because C12 means there's 12 atoms of carbon.
Carbonated drinks are a mixture of many compounds such as glucose(sugar) and others, while water is simply its own molecule.
Answer:
then why'd you ask a question
Explanation: