Periodic Table: A tabular chart representing systematic arrangement of elements in groups and periods, in the order of their increasing atomic numbers is called periodic table.
Modern Periodic Law: The physical and the chemical properties of all elements are the periodic function of their atomic numbers.
Periodicity of Elements: The phenomena due to which elements repeat their properties at regular intervals in a periodic table is called periodicity of elements.
Group: The arrangement of elements in the vertical columns of the periodic table, such that all the elements in it have similar but graded chemical properties is called group.
Period: The arrangement of elements in the horizontal row in the order of their increasing atomic numbers , such that the properties of elements gradually changes from metallic to non-metallic is called period.
Periodic properties: Metallic and non-metallic character, atomic size, ionization potential, electron affinity , and electronegativity are called periodic properties.
Main points of long form of (Modern) Periodic Table):
i) There are 7 horizontal rows, called periods.
ii) There are 18 vertical columns called groups.
iii) The elements occuping left and right wings of vertical column are called normals or representative elements.
iv) The strongly metallic occupy groups I (1A) and 2(IIA) on the extreme left of the periodic table.
v) The strongly non-metallic elements are placed in groups 16(VIA) and 17(VIIA) on the right hand side of periodic table.
vi) The transition elements are accomodate in the middle of the periodic table in 3 rows. They belong to groups 3(IIB) to 12(IIB).
vii) Noble gases (rare gases) are placed in the zero group at the end of the periodic table.
viii) The rare earths (lanthanides) and radioactive elements are kept outside the periodic table to mark their peculiar properties.
Ionization Energy: The energy required to remove one electron from an isolated gaseous atom, theerrby converting it into positively charged ion is called ionization energy or ionization potential.
Electronegativity: The property of an atom to attract electrons to itself , when combined to form a compound is called electronegativity.
Electron affinity: The amount of energy released by an isolated gaseous atom of an element in its lowest state of energy, by accepting on electron to form an ion is called electron affinity.
Characteristics of a group while moving down in a group from top to bottom:
i) The number of electron shells increases by one at each step, such that total number of electron shells in each element represents the period to which the element belongs. For example, if there are three electron shells around the nucleus of an element X , then X belongs to the third period of the periodic table.
ii) The number of valence electrons (electrons in the outermost shell) of each element in a group remains the same.
iii) All the elements in a group have the same valency. The valency is equal to the number of electrons in the valency shell, when compared with oxygen . However, if the valency is compared with hydrogen, then valency is equal to the number of valence electrons for a groups 1(IA) to 13(III A). For the elements of group 14(IVA) to group 17(VIIA) the valency with respect to hydrogen is (valence electrons - 8) and is negative. The valency of zero group element is zero.
iv) The atomic radius increases as one moves down in a group.
v) The nuclear charge(no. of protons) increases as one moves down a group.
vi) a) The metallic character of the elements from 1(IA) to group 13(III A) increases as one moves down a group.
b) The non metallic character of non metallic elements in group 14(IV A) to 17(VIIA), gradually decreases as one moves down the group.
vii) a) The chemical reactivity of elements in groups 1(IA) to 13(III A) increases as one moves down a group.
b) The chemical reactivity of elements in group 14(IVA) to 17(VIIA) decreases as one moves down a group.
viii)a) The melting points of elements in groups 1(IA) to 13(III A) decrease as one moves down a group.
b) The melting points of elements in groups 14(IVA) to 17(VIIA) increase as one moves down a group.
ix) The ionization potential decreases as one move down a group.
x) The electronegativity decreases as one moves down a group.
xi) The electron affinity decreases as one moves down a group.
Characteristics of Periods in the Modern Periodic Table :
a) First period: It has only two elements (hydrogen and helium). It is called very short period.
b) Second and third periods: Both of these periods consists of 8 elements. They are called short periods.
c) Fourth and fifth periods: Both of these periods consists of 18 elements. They are called long periods.
d) Sixth period: It consists of 32 elements. It is called very long period.
e) Seventh period: It is an incomplete period which should have 32 elements. However, so far it has 26 elements. It is also called very long period.
While moving from left to right in a period:
a) The number of electron shells around the nucleus remain the same.
b) The number of electron shells corresponds to the number of period to which the elements belongs.
c) The number of valence electrons increases from 1 to 8 (except in the first group where maximum number of electrons are 2).
d) The valency of an element with respect to oxygen corresponds to the number of electrons in the valence shell. When the valence electrons are 8 (or 2 in the case of helium ), the valency is considered as zero.
e) The atomic size gradually decreases.
f) The nuclear charge gradually increases.
g) The characteristics of an element changes from metallic to non metallic, till at the end of the period, the element is a noble gas.
h) The ionization potential gradually increases.
i) The electron affinity gradually increases.
j) The electronegativity gradually increase.
1) In the long form of periodic table the alkaline earth metals are placed in:
a) group 17 b) group 18 c) group 2 d) group 1
2) Which one is a metalloid ?
a) aluminium b) silicon c) sulphur d) carbon
3) On the basis of electron configuration of valence shell, which one is odd.
a) argon b) krypton c) helium d) neon
4) Which one is in a solid state at room temperature ?
a) Iodine b) bromine c) fluorine d) chlorine
5) Ionization potential increases over a period from left to right, because:
a) atomic radius increases and nuclear charge increases
b) atomic radius decreases and nuclear charge decreases
c) atomic radius increases and nuclear charge decreases
d) atomic radius decreases and nuclear charge increases
6) An element E belongs to period 3 and group 2 will have:
a) three shells in two valence electrons
b) two shells and three valence electrons
c) 3 shells and three valence electrons
d) 2 shells and two valence electrons
7) The term used, when an isolated atom is a gaseous state accepts an electron to form an anion with release of energy is:
a) electron affinity b) ionization potential c) electronegativity d) none
8) An element P has Atomic number 16. The period and group to which P belongs is:
a) period 3 group 6 b) period 3 and group 16 c) period and group 2 d) period 6 and group 16
9) The element P in above is :
a) metal b) metalloid c) non metal d) inert gas
10) As one moves from left to right in a Periodic Table the character of elements change:
a) non-metallic to metallic b) metallic to nonmetallic c) does not change d) none
11) Which one is a metalloid ?
a) silicon b) carbon c) sulphur d) Phosphorus
12) The properties of the elements are periodic function of their:
a) relative atomic mass b) mass number c) atomic number d) both a and b
13) Moving across the period of a periodic table, the elements show increasing:
a) Metallic character b) non metallic character c) electronegativity d) both b and c
14) Compared to an element on the top of group, the element at the bottom of group shows more:
a) Metallic character b) non-metallic character c) atomic volume d) both a and c
15) The similarities in the properties of a group of elements is because they have:
a) same electron configuration b) same number of electrons in valence shell c) same atomic number d) both in a and c
16) Potassium is the element below sodium in the long form of Periodic Table. The electronegativity of potassium will be:
a) lower than sodium b) higher than sodium c) same as sodium d) none
17) Chlorine is the element, below fluorine in the long form of periodic table. The electronegativity of chlorine will be:
a) more than fluorine b) less than fluorine c) same as fluorine d) none
18) Sodium and chlorine are in the same period. The atomic volume of chlorine will be:
a) more than sodium b) less than sodium c) same as sodium d) none
19) An element with atomic number 10 belongs to noble gas family. The family to which element with atomic number 9 belong is:
a) alkali metals b) alkaline earth metals c) halogen d) none
20) Amongst the halogens in group 17, the strongest oxidizing agent is :
a) iodine b) fluorine c) bromine d) chlorine
21) Amongst chlorine, fluorine, iodine and bromine, the least reactive is:
a) chlorine b) iodine c) bromine d) fluorine
22) While moving across a period from left to right, the valence electrons gradually :
a) increase b) decrease c) remain same d) none
23) The element.s which are in liquid state about 30°C are:
a) gallium b) Mercury c) bromine d) all of these
24) The metal which is most powerful reducing agent in a group I metals is:
a) potassium b) rubidium c) sodium d) lithium
25) While moving down in group I the reactivity of elements gradually:
a) increases b) decreases c) remain same d) none
26) The energy required to remove the first electron from the valence shell of an isolated gaseous atom is called:
a) ionization energy b) electron affinity c) ionization potential d) both a and c
27) The largest atomic volume amongst the following is:
a) potassium b) magnesium c) calcium d) sodium
28) The non metals are generally electron acceptors and are good:
a) oxidizing agents b) reducing agents c) catalytic agents d) none
29) Electron affinity is maximum in:
a) alkali metals b) alkaline earth metals c) halogen d) inert gases
30) The energy required to remove an electron from the valence shell of a neutral gaseous atom is called:
a) electron affinity b) electronegativity c) ionization potential d) none
31) Elements belonging the same group have similar properties , because:
a) their atomic number increases as one moves down the group.
b) they are either all metallic or nonmetallic elements.
c) they have similar electron configuration in the valence shell .
d) their number of electrons increases steadily
32) With the increase in atomic number in a period
a) the metallic characters increases b) the metallic character decreases c) the chemical reactivity decreases d) the chemical reactivity increases
33) While moving across period 2 of the periodic table, from the left to right p, the ionization potential gradually:
a) decreases b) first decreases, then increases c) increases d) none
34) While growing down the group 16 of the long form of periodic table, the electron affinity :
a) decreases b) hardly changes c) increases d) none
35) Which of metals in the given above will have largest atomic volume ?
a) Ca b) Ba c) Sr d) Mg
36) Metals are generally :
a) oxidizing agents b) reducing agents c) catalytic agents d) none
37) Amongst Li, Be, C and F, the least atomic size is of:
a) Li b) C c) F d) Be
38) Amongst F, Cl, Br, I the least ionization potential is of:
a) I b) Cl c) Br d) F
39) Amongst Cl, Br, I and F, the element which has highest electron affinity is:
a) I b) Cl c) Br d) F
B) Name the following with reference to the elements of the Modern Periodic Table .
a) An alkali metal in periodic 2.
b) A halogen in period 3.
c) A noble gas having duplet arrangement of electrons.
d) A noble gas having electronic configuration 2, 8.
e) Valency of elements in group I .
f) The number of electron shells in elements of period 3.
g) The metals present in the period 3.
h) The non metals present in period 2.
i) The group of elements having zero valency.
j) A nonmetal in period 3, having valency 1.
k) Formula for hydride of a halogen in period 3.
l) Formula of sulphite of an element present in group 1, period 3.
m) Formula of hydroxide of element having electronic configuration 2, 8, 2.
n) The element in period-3, which does not form an oxide.
o) An element with least atomic size amongst carbon, nitrogen, boron and beryllium
p) The element from elements Li, Na and K having maximum number of electron shells .
q) The elements from elements C, O, N and F having maximum nuclear charge.
r) The element from element Be, Mg, Ca, having lowest nuclear charge.
s) The element from elements fluorine and neon, having higher electron affinity.
t) Period and group of an element X, having electronic configuration 2, 8, 8, 2.
u) The most electronegative element amongst period three elements.
v) The element which has the largest atomic size amongst elements of group 1, 2 and 13.
w) The element, amongst Li, Na, K, which has maximum metallic character.
x) The elements with maximum non metallic characters from the elements period-2.
y) The most non-metallic element from elements S, P, Cl and Ar.
z) The element with the highest ionization potential from the elements of period 1,2 and 3.
C) Complete the following by choosing the correct answers from the bracket.
a) The chemical properties of an element is the periodic function of its___. (mass number/atomic number)
b) The serial number of an element in a Periodic Table is also its____. (mass number/ atomic number)
c) The number of electrons in the valence shell of an element represents its ____. (period/group)
d) The number of electrons shells around the nucleus of an atom represents its ____. (period/group)
e) The strongly active_____(metals/non-metals) are placed in group I A and II A.
f) The ____(metals/nonmetals) are placed on the right hand side of the Periodic Table.
g) The elements placed in the extreme right hand side group are called _____. (noble gases/light gases)
h) The elements occupying the right and left wing vertical columns are called ____(Normal/ transition ) elements.
i) The ______(normal.transition) elements are accommodate in the middle of the periodic table.
j) Hydrogen is a non metal which is placed at the head of a group of most active____. (Non-metal /metals)
C) Match the Columns
Column A Column B
i) period 4 group II A a) Argon
ii) period 2, group III A b) calcium
iii) period 3 group zero c) boron
iv) period 2, group VIA d) silicon
v) period 3, group IVA e) oxygen
D) 2 MARKS QUESTIONS
1a) Name three alkali metals and state their group number.
b) Name three alkaline earth metals and state the group number.
c) Name three halogens and state their group number.
d) Name three noble gases and state their group.
2)a) What do you understand by the term 'Transition elements' ?
b) Select the transition elements from the following list:
List: potassium, calcium, manganese, chromium, copper, calcium, iron, platinum.
3) An element has atomic number 19. Where would you expect this element in the Periodic Table and why ?
4)a) How does the atomic radius change in a period ?
b) element P Q R
At.radius 1.86A° 2.31A° 1.52A°
Arrange the elements in the table above, such that the least metallic element comes first and the most metallic element comes last.
5) Amongst the elements P(at.no 14), Q(at.no 6) and R(at.no 15), which elements have similar chemical properties and why ?
3 Marks Questions
1) An element with atomic number 18 is a noble gas. Into which families will you place elements with atomic number 17 and 19 and why ?
2)a) i) Which period in the Periodic Table is the shortest ?
ii) Name all the elements present in the period.
b) i) Which Period in the Periodic Table is the longest and complete ?
ii) How many elements are present in it?
3) Metallic properties of the elements change to non-metallic properties as one move from left to right in a periodic of the periodic table. explain ?
4) The bigger the atomic volume, more metallic is an element. Explain the statement.
5) i) What do you understand by the term electronegativity ?
ii) Li, Be, B, C, N, O, F, Ne, Na, Mg, Al, Si, P, S, Cl, Ar, K and Ca.
Amongst the list of elements given above pick out.
a) most electropositive element
b) most electronegative element
c) noble gas
6) Why do the halogen atoms have a very strong electron affinity? Explain .
7) i) What do you understand by the term electron affinity ?
ii) Does electron affinity represent energy released or absorbed ?
iii) Name an element having strong electron affinity .
iv) arrange Br, F, I and Cl in the order of increasing electron affinity.
8) Explain why reducing power of elements increases as one goes down a group.
9) Explain why the reducing power of the elements decreases as one moves from left to right in a period ?
10) Why the elements lying on the extreme left hand side group, are very active metals ?
11) Why are the elements lying in a group prior to zero group of the Periodic Table very strong and nonmetals ?
12a) i) Name one most metallic elements in the Periodic Table.
ii) Name one most non metallic element in the Periodic Table.
b) How does electronegativity vary (i) in a period (ii) in a group
13)a) How does ionization potential vary
i) in a period
ii) in a group
b) Table below shows a part of the Periodic Table . State what happens as one moves from left to right to
i) metallic character
ii) atomic radius of elements.
Li Be B C N O F
Na Mg Al Si P S Cl
14) The atom of sodium (at.no 11) is bigger than the atom of chlorine (at. no. 17). Why ?
15) State two merits and two demerits of the long form of the Periodic Table .
5 Marks Questions
1) Use the letters only in the Periodic Table given below to answer the questions that follow:
a) State the number of valence electrons in atom J.
b) Which element shown forms ions with a single negative charge ?
c) Which metallic element is more reactive than R?
d) Which element has its electrons in four shells?
e) Which element has the smallest atomic size ?
2) An element E has atomic number 17. Answer the following questions regarding E:
a) Name the group of E in the long form of periodic table.
b) Name the period of E in the long form a Periodic Table.
c) Is the element E metal or nonmetal ?
d) Name the element E on reacting with burning magnesium will form a compound. Name the formula of the compound.
e) Name the compound formed in (iv) above.
3) An element E has atomic number 14. Answer the following questions .
a) Name the period E belongs to.
b) Write the number of electron shells in E.
c) Write the number of electrons in the valence shell of E.
d) Name the group of element E.
e) Name the element E is.
4) The table given below shows long form of Periodic table. In the table alphabet letters are used rather than symbol of an elements . Answer the following questions :
b) Name the element which forms a negative divalent ion.
c) Name the metallic element more reactive than F.
d) Name the element in which electrons are arranged in 5 shells.
e) Name the kind of chemical bond formed between J and L.
5) An atom A (atomic number 11) and an atom B(atomic number 17) belong to 3rd period of long form of periodic table.
a) Name the atom/s which is/are more metallic among A and B.
b) The (A) and (B) belong to the which families of elements ?
c) Name the type bond formed between A and B is.
d) State the solubility of the compound A and B.
e) What is position of A and B in long form of periodic table ?
6) Amongst E, F, G and H elements, of atomic 4, 9, 15 and 16 respectively.
a) Name the element of the group 17.
b) In the given above the elements which has the three electron shells ?
c) In the given above name the element with highest electronegativity.
d) In the given above which is metal ?
e) In the given above which element is a non metal?
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