Potassium (K) is in Group I of the periodic table, and elements in the same column (period) are similar. Sodium (Na), or lithium (Li) are similar.
Molarity is expressed as:
Molarity = moles / liter
Given that the cell is rod-shaped, its volume is calculated using the formula for a cylinder's volume:
V = πr²L
V = π * (0.6)² * 4.9
V = 5.54 μm³
1 Liter = 10³ mm³
1 mm = 10³ μm
1 mm³ = 10⁹ μm³
1 liter = 10¹² μm³
So the volume in liters is:
5.54 x 10⁻¹² L
Moles = molarity * liters
Moles = 0.0029 * 5.54 x 10⁻¹²
Moles = 1.61 x 10⁻¹⁴
To get the number of molecules, we multiply the moles by Avagadro's number
Number of molecules = 1.61 x 10⁻¹⁴ * 6.02 x 10²³
There are 9.69 x 10⁹ molecules in the cell
Answer: The atomic number is the number of protons in an atom of an element. In our example, krypton's atomic number is 36. This tells us that an atom of krypton has 36 protons in its nucleus.
Explanation:
The daughter isotope (a decay product)of O-15 = N-15(Nitrogen 15)
<h3>Further explanation
</h3>
Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
- alpha α particles ₂He⁴
- beta β ₋₁e⁰ particles
- gamma particles γ
- positron particles ₁e⁰
O-15 emits positron particles ₁e⁰, so the atomic number decreases by 1, the mass number is the same
Reaction

The mass number of the daughter isotope = 15, atomic number = 7
If we look at the periodic system, the element with atomic number 7 is Nitrogen (N)
it means two oxygen atoms