In 1869 Mandeleev put forward his periodic law about:
(d)
The periodic table divided into s, p, d, and f block based on.
(b)
4th and 5th period in periodic table are known as:
(b)
Which one of the following decreases along the period?
(b)
The elements of VIIA group are known as:
(c)
According to Mosely the chemical properties of elements are the periodic function of their:
(d)
The shielding effect across the period :
(d)
The ability to attract shared pair of electron is called:
(b)
In group electron affinity values decreases from top to bottom because:
(b)
All Transition Elements are:
(b)
Who proposed the classification of elements into triads?
Dobereiner proposed the classification of elements into triads where the middle element's atomic mass was approximately the average of the other two elements.
According to Newland's Law of Octaves, how many elements were grouped to show similar properties?
Newland observed that every eighth element had properties similar to the first, similar to musical octaves.
Mendeleev's periodic law was based on:
Mendeleev arranged elements in order of increasing atomic mass and found periodic repetition of properties.
The modern periodic law was proposed by:
Moseley established that atomic number (not atomic mass) is the fundamental property governing periodicity.
The modern periodic table is arranged based on:
Elements are arranged in order of increasing atomic number which equals the number of protons.
How many periods are there in the modern periodic table?
There are 7 horizontal periods in the periodic table, numbered 1 through 7.
The first period of the periodic table contains how many elements?
The first period contains only hydrogen (H) and helium (He) as it fills the K-shell.
Which period is known as the longest period?
The 6th period contains 32 elements including the lanthanide series.
The 14 elements at the bottom of the 6th period are called:
Lanthanides are the 14 f-block elements from cerium (58) to lutetium (71).
Which group of elements is known as alkali metals?
Group IA (Li, Na, K, Rb, Cs, Fr) are called alkali metals due to their ability to form strong alkalis with water.
Alkaline earth metals belong to which group?
Group IIA (Be, Mg, Ca, Sr, Ba, Ra) are called alkaline earth metals.
Which group is known as the halogen family?
Group VIIA (F, Cl, Br, I, At) are called halogens meaning "salt formers".
Noble gases belong to which group?
Group VIII (He, Ne, Ar, Kr, Xe, Rn) are called noble gases due to their inert nature.
Which of the following is a radioactive element in Group IA?
Francium (Fr) is radioactive with no stable isotopes.
Which of the following is a metalloid in Group IIIA?
Boron is the only metalloid in Group IIIA, showing properties intermediate between metals and non-metals.
Which block of the periodic table includes Group IA and IIA elements?
s-block contains elements with valence electrons in s-orbitals (ns¹ or ns² configuration).
The p-block elements include groups:
p-block spans groups 13-18 (IIIA to VIIIA) with valence electrons in p-orbitals.
Transition elements are found in which block?
Transition metals are d-block elements with incomplete d-subshells.
Lanthanides and actinides belong to which block?
Lanthanides (4f) and actinides (5f) are f-block elements with electrons filling inner f-orbitals.
What happens to atomic radius as you move down a group?
Atomic radius increases down a group due to addition of new electron shells.
What happens to atomic radius as you move across a period?
Atomic radius decreases across a period due to increasing nuclear charge pulling electrons closer.
Which of the following has the largest atomic radius?
Rubidium (Rb) is lower in Group IA than the others, thus having more electron shells and larger radius.
Ionization energy is the energy required to:
Ionization energy is the minimum energy needed to remove the most loosely bound electron from a gaseous atom.
Ionization energy generally increases across a period because:
Increased nuclear charge across a period results in stronger attraction to electrons, requiring more energy to remove them.
Which element has the highest ionization energy?
Noble gases (like Ne) have the highest ionization energies due to their stable electron configurations.
Electron affinity is the energy released when:
Electron affinity measures energy change when an electron is added to a neutral atom in gaseous state.
Which halogen has the highest electron affinity?
Chlorine has higher electron affinity than fluorine due to fluorine's small size causing electron-electron repulsion.
Electronegativity is the ability of an atom to:
Electronegativity measures an atom's tendency to attract bonding electron pairs in a covalent bond.
Which element has the highest electronegativity?
Fluorine (F) is the most electronegative element with a value of 4.0 on the Pauling scale.
Which of the following is a liquid halogen at room temperature?
Bromine (Br) is the only liquid halogen at standard temperature and pressure.
Which of the following is a noble gas?
Argon (Ar) is in Group 18 (noble gases) with full valence electron shells.
Which of the following is a property of transition metals?
Transition metals show variable oxidation states due to involvement of both ns and (n-1)d electrons.
The element with atomic number 19 belongs to which group?
Atomic number 19 is potassium (K), an alkali metal in Group IA.
The element with atomic number 17 belongs to which group?
Atomic number 17 is chlorine (Cl), a halogen in Group VIIA.
Which of the following is an alkaline earth metal?
Magnesium (Mg) is in Group IIA, the alkaline earth metals.
Which of the following is a radioactive halogen?
Astatine (At) is radioactive with no stable isotopes.
Which of the following elements is a gas at room temperature?
Chlorine (Cl) is a pale yellow-green gas at standard conditions.
Which of the following has the highest shielding effect?
Rubidium (Rb) has more inner electron shells than the others, providing greater shielding.
The trend of electron affinity in a group is:
Electron affinity decreases down groups as atomic size increases, reducing nuclear attraction for added electrons.
Which of the following is not a trend in the periodic table?
Ionization energy increases across periods due to increasing nuclear charge.
The element with the electronic configuration 2,8,1 belongs to which group?
This configuration (1 valence electron) matches alkali metals in Group IA.
The element with the electronic configuration 2,8,7 belongs to which group?
7 valence electrons indicate halogens in Group VIIA.
Which of the following is a characteristic of noble gases?
Noble gases are inert due to complete valence shells and exist as monatomic gases.