I think the answer is reversible. Reversible reaction is a kind of reaction which can react in both direction at the same time. And when the both side reactions get the same speed, the reaction is at a equilibrium state.
The best way to measure it usually is to use a beaker or graduated cylinder.
It is a very large seamount and island created by hot-spot volcanism
1. The atomic number is equal to the number of protons in the nucleus, and the mass number is equal to the number of protons and neutros in the nucleus.
Therefore, to find the number of neutrons we must do mass number - atomic number, which equals 54.
Answer 1: a. 54
2. Atoms of a same element that have a different number of neutrons in the nucleus are called isotopes of an element.
Answer 2: d. Isotopes
3. Potassium has an electron configuration of , meaning that the first 3 shells are full, and that the last shell (4th one) has only 1 electron.
Answer 3: c. Shells 1, 2 and 3 are full and shell 4 has one electron.
4. An atomic bond isn't a specific bond, it's just a term. Polar covalent and non-polar covalent bonds are strong bonds, which leaves us with the hydrogen bonds, which are indeed the weakest bonds out there.
Answer 4: a. Hydrogen bond
Hope it helped,
BiologiaMagister