Answer: b
explanation: i had the question on a test and got it right.
Answer = B = Neutrons and Mass Number
Isotopes are defined as those atoms which have same atomic number but different atomic masses.
Atomic mass is basically the number of protons and neutrons present in an atom.
Atomic number is the number of protons present in an atom.
So, in isotopes the number of protons are same but the number of neutrons vary due to which atomic masses also vary.
In given three isotopes, all have same number of protons but different number of neutrons.
i.e.
H-1 = 1 P + 0 N = 1 u (Proton)
H-2 = 1 P + 1 N = 2 u (Deuterium)
H-3 = 1 P + 2 N = 3 u (Tritium)
Hence, it is clear that the number after H shows a change in number of neutrons and mass number.
The reactivity of metals increases as you move left in a period and as you move down in a group, so Marie needs to know the period and group of the element inside each box. Boxes that show locations in groups 1 or 2 or in period 8 contain the most reactive elements.
Answer:
The change in concentration of H+ ions is -9.99×10⁻⁵
Explanation:
When pH rises, we talk about neutralization and, there is a decline in proton's concentration.
pH lower than 7 is acid
pH higher than 7 is basic
Protons are neutralized by hydroxides to make water as this:
H₃O⁺ + OH⁻ ⇄ H₂O
pH = - log [H₃O⁺]
[H₃O⁺] = 10^-pH
In conclussion: [H₃O⁺]₁ = 10⁻⁴ → 1×10⁻⁴
[H₃O⁺]₂ = 10⁻⁷ → 1×10⁻⁷
1×10⁻⁷- 1×10⁻⁴
The change in concentration of H+ ions is -9.99×10⁻⁵
