Well, knowing that group 2A elements are metals, and metals lose electrons to gain a full electron shell, we can eliminate B and D. Knowing that these are 2 electrons, that the group 2A element provides to another atom, to form an ion.
The solution is C. Lose 2 electrons.
Answer: The element is represented as Aluminium-27
Explanation:
Atomic number is defined as the number of protons or number of electrons that are present in an electrically neutral atom.
Atomic number = Number of electrons = Number of protons = 13
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons = 13 + 14 = 27
Thus the element with atomic number of 13 is aluminium and its mass number is 27. Thus it is represented as Aluminium-27
Answer:
Option c.
Explanation:
Convection - transfer of heat mode is that technique of transfer of heat in which heat and thermal energy can be transferred from one point to another point in the system by the random movement of the molecules of the fluid. This method of transfer of heat or the mechanism of transfer of heat by convection is the most dominant form of transfer of heat in gases and liquids.
Therefore, we can say that convection involves the transfer of heat as a result of the macroscopic and some random movement of the fluid molecules.
There are 7 periods in the modern periodic table
Answer:
A soap or alcohol will interfere with the hydrogen bonding between water molecules making it weaker
Explanation:
A water molecule is polar as the oxygen atom is strongly electronegative and draws the electrons it shares with the hydrogen atoms in the water molecule to itself. This creates a partial negative charge on the oxygen atom and partial positive charges on the hydrogen atoms. The attraction of neighboring oxygen to hydrogen atoms in a water molecule results in hydrogen bonding.
However, a detergent molecule which has a polar head and a hydrophobic tail, when added to water significantly interferes with the hydrogen bonding between water molecules. The polar head is attracted to water molecules whereas the hydrophobic tail of each molecule are not. The detergent molecules form clusters known as micelles with the polar heads attracted to water and the hydrophobic tails directed towards the center of the micelle, away from water molecules. This weakens the hydrogen bonding between water molecules
An alcohol contains a polar -OH group in its molecules. However, the hydrogen bonding between alcohol molecules are weaker than that in water because the other end of the alcohol molecule has a C-O bond which is less polar than the O-H bond. Therefore, when an alcohol is added to water, it weakens the hydrogen bonding in water.
This weakening of the hydrogen bonding in water also has the effect of lowering the surface tension of water.
