6-0 Periodic Table Beginnings

Who is credited with creating the first widely recognized periodic table in 1869?

• Lothar Meyer

• Dmitri Mendeleev

• Henry Moseley

• Antoine Lavoisier

Answer explanation

Dmitri Mendeleev is credited with creating the first widely recognized periodic table in 1869, organizing elements by atomic mass and properties, which laid the foundation for modern chemistry.

What did Mendeleev use to organize the elements in his periodic table?

• Atomic number

• Atomic mass

• Electronegativity

• Ionization energy

Answer explanation

Mendeleev organized the elements in his periodic table primarily by atomic mass. He arranged them in order of increasing atomic mass, which allowed him to identify patterns and predict the properties of undiscovered elements.

What is the term used to describe the repeating pattern of chemical properties in the periodic table?

• Cyclic

• Periodic

• Linear

• Random

Answer explanation

The term 'Periodic' describes the repeating pattern of chemical properties in the periodic table, reflecting how elements are organized based on their atomic number and similar properties.

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Which element did Mendeleev predict and name as "eka-aluminum" before it was discovered?

• Gallium

• Germanium

• Silicon

• Indium

Answer explanation

Mendeleev predicted the existence of gallium, naming it "eka-aluminum" due to its position in the periodic table below aluminum. Gallium was discovered in 1875, confirming Mendeleev's prediction.

What is the modern periodic table primarily organized by?

• Atomic mass

• Atomic number

• Electronegativity

• Density

Answer explanation

The modern periodic table is primarily organized by atomic number, which reflects the number of protons in an atom's nucleus. This arrangement allows for a clearer understanding of element properties and their relationships.

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Which scientist's work led to the modern organization of the periodic table by atomic number?

• Dmitri Mendeleev

• Lothar Meyer

• Henry Moseley

• Antoine Lavoisier

Answer explanation

Henry Moseley's work in the early 20th century established that atomic number, rather than atomic mass, is the correct basis for organizing the periodic table, leading to its modern structure.

What happens to atomic size as you move from left to right across a period in the periodic table?

• It increases

• It decreases

• It remains the same

• It fluctuates

Answer explanation

As you move from left to right across a period, the atomic size decreases. This is due to the increasing positive charge in the nucleus, which pulls the electrons closer, resulting in a smaller atomic radius.

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What is the trend of electronegativity as you move down a group in the periodic table?

• It increases

• It decreases

• It remains constant

• It fluctuates

Answer explanation

As you move down a group in the periodic table, the electronegativity decreases. This is due to the increasing distance between the nucleus and the valence electrons, which reduces the nucleus's ability to attract bonding electrons.

Which property generally increases as you move from left to right across a period?

• Atomic size

• Electronegativity

• Metallic character

• Density

Answer explanation

As you move from left to right across a period, electronegativity generally increases due to the increasing nuclear charge, which attracts electrons more strongly. In contrast, atomic size decreases and metallic character decreases.

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What is the term for the energy required to remove an electron from an atom?

• Electronegativity

• Ionization energy

• Atomic mass

• Atomic number

Answer explanation

The energy required to remove an electron from an atom is called ionization energy. It reflects how strongly an atom holds onto its electrons, making it a key concept in understanding chemical reactivity.