The ionic radii (it affects the distance between the ions). The charges on the ions If we take the example of sodium chloride and magnesium oxide , both of them have exactly the same arrangements of ions in the crystal lattice, but the lattice enthalpies differ to a great extent. The lattice enthalpy of NaCl is 786 kJmol-1 while the lattice enthalpy of MgO is 3795 kJ mol-1 which is much more than that of sodium chloride. The reason behind such major difference is , the difference in charge of respective ions. In magnesium oxide, 2+ ions are attracting 2- ions, while in sodium chloride, the attraction is only between 1+ and 1- ions.
He proved that 6.022 x 1023 particles are present in 1 mole of a gas. which means if there is 1 mole of Hilum atom, then there are 6.022 x 1023 atoms of Helium. If there is 1 mole of sodium chloride, then there is one mole of Na+ and one mole of Cl- ion in the solid. Also, if there is 1 mole of oxygen molecule, therefor there are 6.022 x 1023 molecule of oxygen atoms At Standard Temperature and Pressure 6.022 x 1023 particles of any gas will occupy 22.4L From this, the number of particles can be found when the volume at STP is given. For example, If 2.24L of oxygen gas at STP has given, then it can be easily conclude that the volume would contain one tenth of the mole of oxygen gas.
The nuclei of these elements fit well in the crystal lattice, but with only three outer shell electrons, there are too few electrons to balance out, and "positive holes" float in the electron cloud. With five outer shell electrons, there are too many electrons. The process of adding these impurities on purpose is called "doping." When doped with an element with five electrons, the resulting silicon is called N-type ("n" for negative) because of the prevalence of free electrons. Likewise, when doped with an element of three electrons, the silicon is called P-type.
A lithium-ion battery is a type of rechargeable battery commonly used for house electronics. When the battery is placed in a device, the positively charged lithium ions are attracted to the cathode and moves towards it. The cathode then becomes more positively charged in comparison to the anode, and this attracts the negatively charged electrons. As the electrons start moving toward the cathode, they go through the device and use the energy of electrons flowing toward the cathode to generate power. When the battery is connected to a charger, the lithium ions move in the opposite direction as the previous direction.
Simplification reduces and changes meaning by narrowing the scope of a knower thus altering understanding. In the process of simplification, we end up excluding valuable information. In O Levels, we were conditioned to think that electrons had fixed positions in their respective atoms because we were given a simple model of an atom. But as higher level students, at the verge of entry into the university, we now know that electrons don’t actually have fixed positions in an atom, they move because they are wave-like and one can only predict approximately, the position of an electron in an atom after applying various theories. In this example, we see that the simple model of an atom excluded vital information that could widen our scope of understanding of the concept of sub-atomic particles.
Energy implies that behavior has strength – that it is relatively strong, intense and persistent. Direction implies that behavior has purpose – that it is aimed or guided toward achieving some particular goal or outcome. (2,3 p.8) The processes that energize and direct behavior emanate from forces in the individual and in the environment. Motives are internal experiences – needs, cognition and emotions – that energize the individual’s approach and avoidance tendencies. External events are environmental, social and cultural offerings that attract or repel the individual to engage in a particular course of action.
In the past, Lion batteries have been lengthily designed as power sources for the portable electrics and lately for electric vehicles. Even though the supercapacitors and lithium-ion batteries have continuously used as a power source in numerous application fields; these two energy storage devices have their lethal disadvantage. Supercapacitors have the weakness of lower energy density while lithium-ion batteries are primarily concerned with the inefficient power density and short cycling life. The way a current difficulty of Li-ion batteries can ultimately overcome is by expanding and contracting the anode when the cells are charged and discharged, to limits the proportion of silicon in the anode to around 10 percent. By using an innovative form of silicon combining with polymer binder does ensure cohesion between binder and silicon but it cannot compromise over the batter lifetime cycle.
It is an effect where the voltage or electric current is created in the material due to exposure to light. It is different from the photoconductive mode. When some light source is shine or enter on the surface of the photodiode, the electron in valence band absorb the light energy or heat energy and turn into excited state, then jump to the conduction band and become free electron. These free electrons will then diffuse or accelerated to other materials and this generates electromotive force or current. This is how light energy is converted to heat energy.