Simplified Chemistry

الثابت العام للغازات : و يرمز له بالرمز R و هو ثابت فيزيائي يستخدم في دراسة خواص الغازات ، ويدخل في عدد كبير من القوانين الفيزيائية المتعلقة بحالة نظام من الغاز من حيث تأثير تغيير حالته عن طريق رفع درجة الحرارة أو الضغط او أنتروبية النظام.   ما هي قيمة الثابت الهعام للغازات R ؟ قيمة R تساوي 0.0821 لتر.ضغط …

Atomic size. The atomic or ionic radius is the size of the atom or the ion of an element and is usually considered as the distance between the nucleus and the outermost shell of the electrons of the atom. Trends in atomic sizes in the periodic table. The atomic size of the elements (atoms) decreases from left to right in …

Electron affinity It is the amount of energy given out when an electron is added to a neutral gaseous atom. This results in the formation of an anion. For example Cl + e– → Cl + energy. The electron affinity of chlorine is 348 kJ mol-1. Electron affinity changes across a period. The electron affinity of the atoms increases from …

Four blocks of elements in the periodic table. 1 –  s block elements. Elements of groups 1 and 2 each possessing one and two electrons respectively in the  s orbital of their outermost orbits are together known as  s block elements. Example :                 Na:  1s2 2s2 2p6 3s1                   Mg:  1s2 2s2 2p6 3s2 Characteristics of s block elements. a -They …

Ionization energy (or potential) of an element is defined as “The amount of energy required or needed to remove an electron from the neutral gaseous atom to form unipositive ion , for example Na → Na+ + e– + energy This is measured in electron volts per atom or kJ mol-1. For example IE of Na is 495 kJ mol-1. …

Shapes  of s and p orbitals s orbital can have only one possible orientation (as it’s m quantum is zero), it is spherical in shape i.e., in an s orbital the electron distribution is symmetrical around the nucleus in all directions. However the size of s orbital depends on principal quantum number. Large n means large size. Thus 3s orbital …

It states that no electron pairing takes place in the p, d and f orbitals until all the orbitals of the given sub-shell contain 1 electron each with parallel spins.

Quantum numbers: These are numbers which are used to specify the location and energy of an electron and size, shape and orientation of the orbital to which a particular electron belongs. Principal or total quantum number (n): This quantum number is identical with that used in Bohr Sommer field theory. It can have only non zero positive integral values. i.e. …

Nature of light and electromagnetic spectrum:  According to Newton’s corpuscular theory, light is propagated as a stream of particles, called corpuscles. This could justify the phenomenon of reflection and refraction of light but failed to explain the phenomenon of diffraction, interference etc. Clerk Maxwell suggested that light waves are associated with both electric and magnetic fields, i.e. light may be …

Bohr’s model of the atom Neil Bohr in 1913 observed that basic features of Rutherford’s atomic model namely presence of nucleus and revolving electrons were correct but that the electrons revolved round the nucleus in certain allowed circular orbits and that the electrons did not radiate and therefore its energy remained constant. However, the electron could jump from outer stationary …