Answer:
D
Explanation:
In a Helium (He) atom, the atomic structure of the atom has 2 protons, 2 electrons and 2 neutrons. For an element X to be a Helium (He) atom, it must possess 2 protons. The number of neutrons present will determine its stability either if its probably radioactive or a natural occurring inert gas.
In option 1,
We have H-2. The symbol "H" is used to denote the element hydrogen in the periodic table and hydrogen has only 1 protons and 1 neutron making its mass number 2.
Option 2,
He -2 : here in this option, we have a helium atom, but with mass number of 2 only. Judging from the formula of mass number = protons + neutrons, we already have proton as 2, hence the number of neutrons there is zero (0)
Option 3,
He - 3 : just like in option 2, the only difference here is that the mass number is 3 hence making the number of neutrons just 1.
Option 4,
He - 4 : This option met the requirements of having 2 protons and 2 neutrons making a total of 4 which corresponds to the mass number.
The periods are the rows, and there are 8 of them (I think)
The physical properties of a metal depend on how dense the metal is
Answer: 1.05
Explanation:
On ionization, hydrobromic acid completely dissociates into hydrogen ion and bromine ion. The equation is stated below
HBr <--> H+ + Br-
Recall that pH = - log(H+)
Concentration of hydrogen ion (H+) = 0.09M
So, pH = - log (0.09)
pH = - (-1.05)
pH = 1.05
The pH of 0.09M solution of HBr is 1.05. Thus, it is highly acidic.
