Answer:
The first five elements of the periodic table are:- hydrogen, helium, lithium, beryllium, boron
Explanation:
atomic number- it is represented by the letter Z. It is basically the total number of protons present in each atom's nucleus of that element.
atomic mass- is the mass of a single atom present in the element.
electrons and protons- they are negatively and positively charged particles found in the nucleus of the atom respectively.
neutrons- they have no or zero charge and weigh more than protons.
element | atomic number | atomic mass | electrons | protons | neutrons
hydrogen (H)- 1 | 1.008 | 1 | 1 | 0
helium (He) - 2 | 4.0026 | 2 | 2 | 2
Lithium (Li) - 3 | 6.94 | 3 | 3 | 4
beryllium (Be) - 4 | 9.0122 | 4 | 4 | 5
Boron ( B) - 5 | 10.81 | 5 | 5 | 6
Answer:
1. Absorbs electromagnetic energy
2. Energy difference between the two orbits.
Explanation:
Bohr precisely describe the processes of absorption and emission of energy in terms of electronic structure. According to Bohr's model, an electron would absorb energy in the form of photons to get excited to a higher energy level as long as the photon's energy was equal to the energy difference between the initial and final energy levels. After jumping to the higher energy level or the excited state, the excited electron would be in a less stable position, so it would quickly emit a photon to relax back to a lower, more stable energy level.
Answer:
H+ + OH− --> H2O
Explanation:
Hydrochloric acid is represented by the chemical formular; HCl. This is an ionic substance so in water it breaks apart into hydrohrn ions; H+ and chloride ions; Cl−. It is a strong acid, hence it completely dissociates.
Potassium Hydroxide is also an ionic substance it also breaks apart in water into potassium ions; K+ and hydroxide ions; OH−. It is a strong base, hence it completely dissociates.
The complete ionic equation for the reaction is given as;
H+ + Cl− + K+ + OH− --> K+ + Cl− + H2O
The Hydrogen ion and the Hydroxide ions combine to form water.
The net ionic equation is given as;
H+ + OH− --> H2O
Cl- and K+ ions were cancelled out because they do not undergo any changes therefore are not part of the net ionic equation. They are referred to as spectator ions.
This is true do to all the other particules around
First, find the volume the solution needs to be diluted to in order to have the desired molarity:
You have to use the equation M₁V₁=M₂V₂ when ever dealing with dilutions.
M₁=the starting concentration of the solution (in this case 2.6M)
V₁=the starting volume of the solution (in this case 0.035L)
M₂=the concentration we want to dilute to (in this case 1.2M)
V₂=the volume of solution needed for the dilution (not given)
Explaining the reasoning behind the above equation:
MV=moles of solute (in this case KCl) because molarity is the moles of solute per Liter of solution so by multiplying the molarity by the volume you are left with the moles of solute. The moles of solute is a constant since by adding solvent (in this case water) the amount of solute does not change. That means that M₁V₁=moles of solute=M₂V₂ and that relationship will always be true in any dilution.
Solving for the above equation:
V₂=M₁V₁/M₂
V₂=(2.6M×0.035L)/1.2M
V₂=0.0758 L
That means that the solution needs to be diluted to 75.8mL to have a final concentration of 1.2M.
Second, Finding the amount of water needed to be added:
Since we know that the volume of the solution was originally 35mL and needed to be diluted to 75.8mL to reach the desired molarity, to find the amount of solvent needed to be added all you do is V₂-V₁ since the difference in the starting volume and final volume is equal to the volume of solvent added.
75.8mL-35mL=40.8mL
40.8mL of water needs to be added
I hope this helps. Let me know if anything is unclear.
Good luck on your quiz!
