<u>Answer:</u> The given example is a physical change.
<u>Explanation:</u>
A chemical change is defined as the change in which chemical composition of a substance changes and results in the formation of a new substance. These are usually irreversible process.
A physical change is defined as the change in which only the shape and size of the substance changes and no new substance is formed. Only phase change occurs in these processes. These are usually considered as a reversible change.
For the given example: Moisture in the air forms beads of water on a cold window pane.
This is a physical change because water was initially present in the gaseous state (Moisture in the air) and when it is coming in contact with the cold window pane, the gaseous state of water gets converted into a liquid state.
Hence, the given example is a physical change.
There appears to be no table shown, but I can still answer. Aluminum has 3 valence electrons
Answer:
Hence among the options a and c, option d is that the correct answer because it has rock bottom energy ( as n value increases, energy decreases as energy levels come closer).
Explanation:
The relation between energy and wavelength is:
From this equation, it's clear that wavelength and energy are inversely proportional to every other. The Lower the energy of a specific transition, the longest will the wavelength be of that specific transition.
Among the given options, options b and d are often ruled out, since those transitions produce to release of a photon because it is coming down from an excited state.
Answers:
Hydrogen bond is formed when positive end of one molecule attracted negative end of other molecule. The concept is similar to magnetic attraction where opposite poles attract each other.
Explanation:
While understanding hydrogen bond, two terms are important, one is electronegativity (tendency of atoms to attract electrons towards itself) and other is dipole (separation of positive and negative charge in a molecule). Hydrogen bond is always formed between hydrogen atom and other atoms having electronegativity different than hydrogen.
Differ from Ionic and Covalent Bonds:
Hydrogen bond is weaker than ionic and covalent bond. Ionic and covalent bonds are intramolecular (within the molecule) whereas hydrogen bond is intermolecular (between molecules).
Example:
Formation of hydrogen bonding in water.
