Answer:
The correct answer is C: A radiation consisting of uncharged particles is emitted when alpha particles strike beryllium atoms.
Explanation:
Chadwick discovered neutron while experimenting with a gold foil. A stream of alpha particles produced from a polonium source was directed at beryllium target. It was noticed that some penetrating radiations were produced. These uncharged particles were called neutrons because on the charge detector these particles showed no deflection.
Their nuclear reaction is as follow.
₂He + ₄Be ----------> ₀n + ₆C
Chadwick noticed that neutrons cannot ionize gases and are highly penetrating particles.
Answer:
Mass of NaF in 250 g tube of toothpaste = 100 mg of NaF
Explanation:
Mass of fluoride per gram of toothpaste = 1 mg
From the given data, the fluoride compound that is most often used in toothpaste is sodium fluoride, NaF, which is 45% fluoride by mass, mass of sodium fluoride per gram of toothpaste can be determined as follows:
1 mg of fluoride per gram of toothpaste = 45% total mass of NaF per gram of toothpaste
100% mass of NaF in toothpaste = 100/45 * 1 mg = 2.22 mg of NaF.
Therefore, mass of NaF per gram of toothpaste is 2.22 mg.
The mass of NaF in 250 g of toothpaste is then calculated below:
In 250 g of toothpaste, mass of NaF = 250 * 2.22 mg = 99.9 mg of NaF
Answer:
Three
Explanation:
1. Draw a Lewis structure
- Put the least electronegative atom (C) in the centre
- Attach the O and two S atoms to the C.
- Add enough electrons to give each atom an octet.
2. Draw the resonance structures
You should get one of the structures below.
It has a double bond and two single bonds.
The resonance structures will have the double bond in each of the other two positions.
