The mass number of aluminium is 26 and the atomic number of aluminium is 13.
The number of neutrons is given by the difference between the mass number and number of protons.
number of neutrons = mass number - number of protons
Number of protons = 13
Mass number of Aluminium = 26
Therefore number of neutrons = 26-13 = 13.
The atomic number of thorium is 90 and the mass number of thorium is 230 as given in the question
atomic number = number of electrons = number of protons
Therefore the number of electrons in thorium 230 = 90
Number of protons in thorium 230 = 90
Number of neutrons = Mass number - number of protons = 230-90 = 140
Answer:
Samira's model is incorrect because not all atoms are accounted for
Explanation:
The image of Samira's model has been attached to this answer to enhance the explanation.
What is depicted in that model is rightly regarded as a chemical change. In a chemical change atoms of substances are rearranged as new substances are formed.
However, all atoms in the products must also be found in at least one of the reactants. In this case we have an atom in one of the products that is not accounted for. Hence the model is incorrect.
Answer:
1st paragraph:
1.compound 2.physical 3.elements 4.water 5. gas 6.white 7. season 8.ratio 9.formula 10.elements 11.atoms 12.subscript 13.one
2nd paragraph
1.stable 2.many/reactive 3.eight 4.helium 5.seven 6.outer 7.one 8.level 9. compounds 10.reactive 11. seven 12. Eight 13.lose 14.gain 15. Share 16.compounds 17. atoms
Explanation:
I just did the 1st page. Gimme a min and I'll do the second.
Answer:
answer is C
Explanation:
encourage the release of carbon dioxide from the stems
