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.
Answer:
Nitrogen and Oxygen make up 99% of the Earths atmosphere. Then Argon makes up the rest of the atmosphere.
Answer:
Umm i dont know but i think atomic nucleus
Explanation:
Answer:
A) litmus is red
Explanation:
To answer this question, it can be helpful to have the color charts. Litmus, phenolphthalein and methyl orange are ways to test the pH of a substance.
<u>Litmus paper</u>
Litmus can tell you if a substance is an acid or a base. You need to put the substance on both red litmus and blue litmus paper.
pH < 7: both papers are red. 3.0 is less than 7.
pH = 7: none of them change color
pH > 7: both papers are blue
<u>Phenolphthalein</u>
When this indicator is added to a substance, the result is either colorless or pink.
0 < pH ≤ 7: colorless. The color is not red or blue for pH 3.0.
pH > 7: pink
<u>Methyl orange</u>
0 < pH < 4: red. The color is not yellow if the pH is 3.0.
4 ≤ pH < 5: orange
pH ≥ 5: yellow