Historical Development of the Periodic Table
Who is considered the father of the periodic table?
Dmitri Mendeleev
What is the main principle behind the modern arrangement of the periodic table?
Elements are arranged in order of increasing atomic number.
How are elements with similar chemical properties arranged in the periodic table?
They are arranged in vertical columns called groups or families.
What is the group of element Z if the proton number is 3?
Group 1
Which scientist's work led to the modern atomic number arrangement of the periodic table?
Henry Moseley
How many periods are there in the modern periodic table?
Seven
What determines the position of an element in a period (horizontal row) in the periodic table?
The number of electron shells (energy levels) in the atom.
What is the period of element Y if the proton number is 15?
Period 3
Which early chemist grouped elements into triads based on similar chemical properties?
Johann Wolfgang Döbereiner
What is the term for the horizontal rows in the periodic table?
Periods
Why do elements in the same group have similar chemical properties?
They have the same number of valence electrons.
What is the proton number of element A if the electronic configuration is 2.8.2?
12
What was Mendeleev’s major contribution to the periodic table?
He arranged elements by increasing atomic mass and left gaps for undiscovered elements.
Question 3: What name is given to the vertical columns in the periodic table?
Groups
What is the proton number of element B if the electonic configuration is 2.8.7?
17
What was the significant difference between Mendeleev’s periodic table and the modern periodic table?
Mendeleev’s table was arranged by atomic mass, while the modern table is arranged by atomic number.
Give the position of element X in the periodic table if the proton number is 17.
Group 17, Period 3