Answer:
Explanation:
Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
In 1897, J.J. Thomson discovered the electron by experimenting with a Crookes, or cathode ray, tube. He demonstrated that cathode rays were negatively charged. In addition, he also studied positively charged particles in neon gas.
Rutherford overturned Thomson's model in 1911 with his well-known gold foil experiment in which he demonstrated that the atom has a tiny and heavy nucleus. Rutherford designed an experiment to use the alpha particles emitted by a radioactive element as probes to the unseen world of atomic structure.
The Bohr model shows the atom as a small, positively charged nucleus surrounded by orbiting electrons. Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.
Answer: A boron atom has 2 electrons at the first energy level and 3 electrons at the second energy level.
Answer:
ESCALAS MAYORES (D, E, G, A, B) Porfavor necesito ayuda,te lo agradecería muchísimo!!
Es urgente
Stirring and agitating chemical reactions is desirable and stirring reflux systems or any system under heating is necessary to a distribute the heat evenly throughout the system and b) to prevent splashing and boilovers.
The balanced equation is
4Fe+3O₂⇒2Fe₂O₃
We know that the mole of Fe₂O₃ is 6, and since the ratio between oxygen and <span>Fe₂O₃ is 3:2, we can see that
3:2 = x:6 (3 oxygen moles can make 2 </span>Fe₂O₃ moles = x oxygen moles can make 6 <span>Fe₂O₃ moles)
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Multiply outside and inside (3*6 , 2*x) and put them on opposing sides of the equation
2*x = 3*6
2x=18
x=9
Therefore 9 moles of oxygen is needed.
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