$CATEGORY: Science - Khan Academy/5.Periodic Classification of Elements/5.Periodic Classification of Elements--Making Order Out of Chaos-The Modern Periodic Table

//Multiple Choice

What happens to the atomic radius as we move from left to right across a period in the periodic table?
{
  ~ Increases
  = Decreases
  ~ Remains constant
  ~ None of the above
}

Why does the atomic radius decrease across a period?
{
  ~ Increase in the number of shells
  = Increase in nuclear charge
  ~ Decrease in nuclear charge
  ~ Addition of electrons in new shells
}

What happens to the atomic radius as we move down a group in the periodic table?
{
  = Increases
  ~ Decreases
  ~ Remains constant
  ~ First increases, then decreases
}

Why does the atomic radius increase down a group?
{
  ~ Decrease in nuclear charge
  ~ Addition of protons
  = Addition of electron shells
  ~ Decrease in shielding effect
}

Which element has the smallest atomic radius in the periodic table?
{
  ~ Hydrogen
  = Helium
  ~ Lithium
  ~ Fluorine
}

Which of the following has the largest atomic radius in Group 1?
{
  ~ Lithium
  ~ Sodium
  ~ Potassium
  = Cesium
}

How does the shielding effect influence atomic radius down a group?
{
  ~ It decreases atomic radius
  = It increases atomic radius
  ~ It has no effect on atomic radius
  ~ It first increases and then decreases atomic radius
}

What is the trend in atomic radius for noble gases in a period?
{
  = Largest in the period
  ~ Smallest in the period
  ~ Same as alkali metals
  ~ Same as halogens
}

In the second period, which element has the smallest atomic radius?
{
  ~ Lithium
  ~ Boron
  ~ Fluorine
  = Neon
}

Which of the following statements about atomic radius is correct?
{
  ~ Atomic radius increases with increasing nuclear charge across a period.
  ~ Atomic radius decreases with increasing number of shells down a group.
  = Atomic radius decreases across a period due to increasing effective nuclear charge.
  ~ Atomic radius remains constant across a period.
}

//True or False

Atomic radius decreases across a period due to an increase in the shielding effect. {F}

The atomic radius increases down a group because new electron shells are added. {T}

Noble gases have the smallest atomic radii in their respective periods. {F}

The atomic radius of elements is measured in picometers (pm). {T}

The atomic radius of cesium is larger than that of lithium. {T}

Effective nuclear charge decreases across a period, leading to an increase in atomic radius. {F}

Atomic radius is inversely proportional to the nuclear charge in a period. {T}

The atomic radius of transition metals remains almost constant across a period. {T}

The atomic radius of an anion is smaller than its parent atom. {F}

The atomic radius of elements in Group 17 is smaller than those in Group 1 of the same period. {T}


//Fill in the blanks

The atomic radius of elements __________ as we move from left to right across a period.
{
  ~ Increases
  = Decreases
  ~ Remains constant
  ~ fluctuates
}

The atomic radius __________ as we move down a group in the periodic table.
{
  ~ Decreases
  = Increases
  ~ Remains the same
  ~ first increases, then decreases
}

The decrease in atomic radius across a period is due to an increase in __________.
{
  ~ number of shells
  = nuclear charge
  ~ shielding effect
  ~ atomic mass
}

The increase in atomic radius down a group is due to the addition of __________.
{
  ~ protons
  = electron shells
  ~ neutrons
  ~ nuclear charge
}

In a period, the element with the largest atomic radius is generally a __________.
{
  ~ noble gas
  ~ halogen
  = alkali metal
  ~ transition metal
}

In Group 1, the element with the smallest atomic radius is __________.
{
  = Lithium
  ~ Sodium
  ~ Potassium
  ~ Cesium
}

The atomic radius of noble gases is __________ compared to other elements in the same period.
{
  = larger
  ~ smaller
  ~ the same
  ~ unpredictable
}

The atomic radius of fluorine is __________ than that of oxygen.
{
  ~ larger
  = smaller
  ~ equal
  ~ unpredictable
}

As we move across a period, the effective nuclear charge __________, causes a decrease in atomic radius.
{
  ~ decreases
  = increases
  ~ remains constant
  ~ fluctuates
}

The trend of increasing atomic radius down a group is primarily due to the __________ effect.
{
  ~ nuclear charge
  = shielding
  ~ ionic
  ~ magnetic
}

//Numericals

If the atomic radius of Lithium is 152 pm and that of Beryllium is 112 pm, what is the difference in their atomic radii?
{
  ~ 30 pm
  = 40 pm
  ~ 50 pm
  ~ 60 pm
}

The atomic radius of an element decreases from 200 pm to 180 pm as we move across a period. What is the percentage decrease?
{
  ~ 5%
  = 10%
  ~ 20%
  ~ 25%
}

In Group 1, the atomic radius of Sodium is 186 pm, and that of Potassium is 231 pm. What is the increase in atomic radius?
{
  ~ 35 pm
  = 45 pm
  ~ 50 pm
  ~ None of the above
}

If the atomic radius of Neon is 38 pm and that of Fluorine is 42 pm, what is the difference between them?
{
  ~ 2 pm
  = 4 pm
  ~ 6 pm
  ~ 8 pm
}

The atomic radius of Chlorine is 99 pm, and Bromine is 114 pm. What is the ratio of their atomic radii?
{
  ~ 11\:10
  ~ 10\:11
  = 5\:6
  ~ 6\:5
}

If the atomic radius of Magnesium is 160 pm and Calcium is 197 pm, by how much does the radius increase?
{
  ~ 27 pm
  = 37 pm
  ~ 47 pm
  ~ 57 pm
}

The atomic radius of Hydrogen is 53 pm. What will be the radius of two Hydrogen atoms in a molecule?
{
  ~ 53 pm
  = 106 pm
  ~ 159 pm
  ~ 212 pm
}

The atomic radius of an element is 120 pm. What is its radius in nanometers (nm)?
{
  ~ 0.012 nm
  = 0.12 nm
  ~ 1.2 nm
  ~ 12 nm
}

If the atomic radius of Boron is 88 pm and that of Aluminium is 143 pm, what is the percentage increase?
{
  ~ 50%
  ~ 60%
  = 62.5%
  ~ 70%
}

The atomic radius of Argon is 71 pm, and that of Krypton is 88 pm. What is the absolute difference in their radii?
{
  ~ 10 pm
  ~ 15 pm
  = 17 pm
  ~ 20 pm
}

//Match the following

Match the following items from Column A with their correct corresponding options from Column B\:
{
  = Lithium -> 152 pm
  = Sodium -> 186 pm
  = Potassium -> 231 pm
  = Cesium -> 298 pm
}


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