S-block consists of metals ( alkali metals and Alkaline Earth metals ) , the metals form oxides which are basic in enough. This means when the oxides of the metals are made to react with water they form bases. For example Sodium is an s-block , when sodium oxide is made to react with water,Continue reading “How nature of oxides formed by s and p-block elements vary across a period .”
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Ionization energy down the group.
Ionization energy is the minimum amount of energy required to completely remove electron (s) from a neutral atom in gaseous state . The ionization energy of the elements within a group generally decreases from top to bottom. This is due to electron shielding/screening. Screening is the ability of atoms inner electrons to shield it’s positivelyContinue reading “Ionization energy down the group.”
Atomic sizes across a period.
Atomic sizes ( in terms of radius) gradually decrease from Left to right across a period of elements. This is because within a period, all electron (s) are added to the same shell . However, at the same time the protons are being added to the nucleus making it more positively charged. The effect ofContinue reading “Atomic sizes across a period.”
Diagonal relationship
Is the similarities in properties ( chemical and physical ) observed between two elements placed diagonally from left to right in two adjacent groups in the periodic table of elements. The diagonal relationship is due to the polarizing power, i.e , ionic charge/radius being similar for diagonally placed elements. E.g lithium and Magnesium, Beryllium andContinue reading “Diagonal relationship”
Sodium is harder than potassium metal . Explain?
The smaller the atom in term of atomic radius,the higher the melting point of an element and hence the greater the metallic bond in the metals . Sodium has a smaller atomic radius ( atomic radius of the Alkali metals increases down the group) than potassium metal, therefore the orbital are nearer to the nucleusContinue reading “Sodium is harder than potassium metal . Explain?”
Ist and 2nd electron affinity of oxygen atom
1st electron affinity is usually exothermic as the energy released when the nucleus attracts additional electron is larger than the energy absorbed to overcome inter-electronic repulsion. 2nd electron affinity is always endothermic since an additional electron is added to a negative ion . Energy is absorbed to overcome inter-electronic repulsion between two negatively charged speciesContinue reading “Ist and 2nd electron affinity of oxygen atom”
Atomic size down group 13 elements.
The elements in group 13 ( p-block) have smaller atomic radius compared to the s block elements . However, the trend in atomic radius do not vary in a regular manner down the group. The atomic radius of Ga (135 pm) is slightly less than that of Al ( 143 pm) . This is becauseContinue reading “Atomic size down group 13 elements.”
Catalytic activity of transition elements
Transition elements are good homogeneous and heterogeneous catalysts. This is because they are able to form numerous oxidation state and are able to form unstable intermediate compound during a reaction providing an alternative route with a lower activation energy. Vanadium (v) oxide V2O5 is used in oxidation of SO2 to SO3 in contact process( industrialContinue reading “Catalytic activity of transition elements”
Characteristics of transition metals .
A transition element is one whose atom has a partially filled d or f sub-shell or which can give rise to cations with a partially filled d or f sub-shell. This therefore, includes the f-block elements (also known as the inner transition elements) Transition elements are located in between the s-block and p- block elementsContinue reading “Characteristics of transition metals .”
In terms of structure and bonding, explain why Hydrogen sulphide exist in gaseous state ( low boiling point) while water exist in liquid form ( high boiling point) ?
Both water and hydrogen sulphide gas have molecular structures or are molecular substances (made up of molecules) . For molecular substances, increase in molecular mass leads to increase in melting point and boiling point. Water has a molecular mass of 18g/mol and hydrogen sulphide has a molecular mass of 34g/mol , so it is expectedContinue reading “In terms of structure and bonding, explain why Hydrogen sulphide exist in gaseous state ( low boiling point) while water exist in liquid form ( high boiling point) ?”
In terms of structure and bonding, explain why SO2 have a low boiling point while SiO2 have a high boiling although both have a covalent bond in between the atoms ?
Both Si02 and SO2 have covalent bonds in between their atoms , but SO2 have a molecular structure while SiO2 have a giant atomic structure. SO2 exist in gaseous form and have covalent bond in between their atoms and weak Van der Waals in between the molecules which are weak to break hence has aContinue reading “In terms of structure and bonding, explain why SO2 have a low boiling point while SiO2 have a high boiling although both have a covalent bond in between the atoms ?”
Why is an atom said to be electrically neutral?
In any given atom, the number of protons in the nucleus of an atom equals to the number of electrons in the energy level. The protons are positively charged while the electrons are negatively charged. For example, a sodium atom has 11p ,11e and 12n , the neutrons have no charge. The protons therefore hasContinue reading “Why is an atom said to be electrically neutral?”
Explain why hydrogen can be regarded as either a group i element or a group vii elements in the periodic table of the first 20 element ?
Explanation Hydrogen is the lightest element with 1 atomic mass unit , it is the first element in the first 20 elements in the periodic table, hydrogen exists in form of several isotopes . Hydrogen is found in combined form with other elements such as with oxygen to make up water and also in hydroxidesContinue reading “Explain why hydrogen can be regarded as either a group i element or a group vii elements in the periodic table of the first 20 element ?”
Isotopes
Isotopes are atoms of the same element, with the same atomic numbers but different mass numbers . Why do isotopes occur ? This is due to the difference in the number of neutrons in the nucleus of these atoms . Carbon has two isotopes, Carbon -12 and Carbon – 14 . Browse on
The first 20 element in the periodic table
The periodic table consists of elements arranged according to their atomic numbers . In this sub topic , we will look at those element from atomic number 1 to 20 . Am sure almost every learner develops a way of identifying the elements in an order starting with the 1st to the 20th . HiContinue reading “The first 20 element in the periodic table”
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