Test: Periodic Classification of Elements - 1 - UPSC MCQ

In chemistry, a group (also known as a family) is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the periodic table. 

Modern periodic law was proposed by Henry Moseley in 1913. According to the modern periodic law, the properties of the elements and their compounds are a periodic function of their atomic numbers..

The group 1 elements in the periodic table are known as the alkali metals. They include lithium, sodium and potassium, which all react vigorously with air and water.

The correct answer is option 3: Cl (chlorine). Among the elements listed, chlorine (Cl) has the smallest size in the third period of the periodic table. Sodium (Na) and silicon (Si) are in the third period as well but have larger atomic sizes. Argon (Ar) is a noble gas and is not in the same period as the other elements mentioned.

The correct option is C.
 The characteristic chemical property of a metal atom is to lose one or more of its electrons to form a positive ion. However, certain metals lose electrons much more readily than others. In particular, cesium (Cs) can give up its valence electron more easily than can lithium (Li).

An English scientist called John Newlands put forward his law of octaves in 1864. He arranged all the elements known at the time into a table in order of relative atomic mass. When he did this, he found that each element was similar to the element eight places further on.

A period is a horizontal row of the periodic table. There are seven periods in the periodic table, with each one begining at the far left.

Non metallic character decreases as we move down the group. In a group, the size of an element increases because there is an addition of new shell and electron  is added in that shell. Hence, fluorine has the most non metallic character. 

We know, Phosphorus ( P) belongs to group 15 , Sulphur (S) belongs to group 16 and chlorine belongs to group ( 17) . So, option ( c) is the correct one.

As we can see, the no. of electrons in the valence shell of oxygen (8) is => 6
In valence shell of carbon (6) => 4
In valence shell of Nitrogen (7) => 5
In valence shell of  boron (5) =>  3 
Therefore, boron has the lowest electron in the valence shell. 

The valence electrons of the atomic number 15 has 5 electrons in its outermost shell . Nitrogen also has 5 electrons in it's outer shell. It also belongs to 15 th group and has same chemical properties, others  have 2,8 and 6 in their outermost shell. 

The atomic size of Be is 112 pm, the atomic size of C is 70 pm, the atomic size of oxygen is 60 pm and the atomic size of fluorine is 71 pm. So, the atomic size of Be is largest here. 

The correct answer is B as elements of group Na form XCl halide. 
Elements of group Mg form XCl2 halide. 
Elements of group Al form XCl3  halide. 
Elements of group Si form XCl4  halide. 
As an element, X forms a chloride with the formula XCl2  which is solid with a high melting point. X would most likely be in the same group of Mg. 

Metallic character decreases across a period from left to right. On the other hand non-metallic character increases with increase in atomic number across a period.

The element with atomic number 20 is Calcium (Ca) and it has metallic character as it loses two valence electrons easily to complete it's octet. 

Many scientists describe a "transition metal" as any element in the d-block of the periodic table, which includes groups 3 to 12 on the periodic table. In actual practice, the f-block lanthanide and actinide series are also considered transition metals and are called "inner transition metals".

There are a number of properties shared by the transition elements that are not found in other elements, which results from the partially filled d shell. These include
1. the formation of compounds whose color is due to d–d electronic transitions
2. the formation of compounds in many oxidation states, due to the relatively low energy gap between different possible oxidation states[
3. the formation of many paramagnetic compounds due to the presence of unpaired d electrons. A few compounds of main group elements are also paramagnetic (e.g. nitric oxide, oxygen)

The correct answer is D as All of them have  valence electrons equal to seven and this can accept one electron to complete their octet

The carbon group is a periodic table group consisting of carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). It lies within the p-block. In modern IUPAC notation, it is called Group 14.

In 1864, Newlands arranged the known 56 elements in the order of increasing atomic masses. He observed that the properties of every eighth element are similar to the properties of the first element. Based on this observation, he proposed the Law of Octaves for the classification of elements. Law of Octaves: When the elements are arranged in the increasing order of their atomic masses, the properties of every eighth element are similar to the first.