Answer:
Water is a human necessity. Therefore, it is one of the first things a human settlement would need to have. A community cannot thrive without a water source.
B. Lower elements have more energy levels
Explanation:
Ionization energy decreases down the group because lower elements have more energy levels. Therefore, the pull of the nucleus on the outermost shell electrons is not so great.
- Ionization energy is the energy required to remove an electron from an atom.
- It is a measure of the readiness of an atom to lose an electron.
- Down a group or family, atomic radius increases due to addition of more electronic shells or energy levels.
- As the atomic radius becomes larger, the ionization energy reduces.
- This is because of the increased shielding/screening effect of inner shell electrons on the electron to be removed from the nuclear attraction.
- This way, its takes a lesser amount of energy to remove them as shielding effects increases down the group.
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Answer:
Endothermic reaction
Explanation:
Endothermic reactions are defined as the type of chemical reaction in which the system absorbs the energy from the surroundings and the temperature of the surrounding decreases while in Exothermic reactions, heat is released by the system to the surroundings and it makes the surrounding warm.
The given example is an "endothermic reaction" because the reaction between NH4Cl and water is making the surrounding cool (cold pack) due to the release of heat.
Hence, the correct answer is "endothermic reaction".
The chemical symbol for the starting substance is A. NaCl
and the end is
B. NaOH
Answer:
sory Idont know Iwish you answer this question