periodic table

Sure! Below are the flashcards covering all the points from the introduction to the periodic table and related concepts:

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### Introduction to the Periodic Table
1. Front: What is the periodic table?
Back: It is a table that classifies all known elements based on their properties, grouping similar elements in the same vertical column and separating dissimilar ones.

2. Front: How are the 115 known elements arranged in the periodic table?
Back: They are arranged in order of increasing atomic number.

3. Front: What are the vertical columns in the periodic table called?
Back: Groups.

4. Front: What are the horizontal rows in the periodic table called?
Back: Periods.

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### Approaches to Periodic Classification of Elements
5. Front: What is Dobereiner’s Triads?
Back: Dobereiner classified elements into groups of three (triads) where the atomic mass of the middle element is the average of the other two.

6. Front: What is Newlands’ Law of Octaves?
Back: Newlands noticed that elements showed similar properties every eighth element when arranged by atomic mass, similar to the octaves in music.

7. Front: What is Lother Meyer’s Law?
Back: Lother Meyer proposed that atomic volume is a periodic function of atomic mass.

8. Front: What is Mendeleev’s Periodic Law?
Back: Mendeleev stated that the properties of elements are periodic functions of their atomic masses. Elements with similar properties recur at regular intervals.

9. Front: What are the anomalies in Mendeleev’s table?
Back:
- Position of hydrogen
- Position of rare earths
- Position of isotopes
- Position of noble gases
- Anomalous pairs of elements
- Cause of periodicity

10. Front: What is the Modern Periodic Law?
Back: The physical and chemical properties of elements are periodic functions of their atomic numbers.

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### Long Form of the Periodic Table
11. Front: How is the long form of the periodic table organized?
Back: It is based on the modern periodic law, where elements are arranged by increasing atomic number.

12. Front: What are the periods in the periodic table?
Back:
- The first period has 2 elements.
- The second and third periods have 8 elements each.
- The fourth and fifth periods have 18 elements each.
- The sixth period has 32 elements.
- The seventh period is incomplete.

13. Front: How many groups are in the modern periodic table?
Back: There are 18 vertical columns called groups, arranged from IA to XVIII.

14. Front: What determines a group in the periodic table?
Back: A group is determined by the number of electrons in the outermost shell of an element.

15. Front: What are the different types of elements in groups?
Back:
- Groups 1, 2, and 13–17: Normal elements.
- Groups 3–12: Transition elements.
- Group 18: Noble gases.

16. Front: Where are reactive metals and non-metals placed?
Back:
- Reactive metals: Groups 1 and 2.
- Transition metals: Middle of the table.
- Non-metals: Upper right corner.

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### Periodicity
17. Front: What is periodicity?
Back: It refers to the repetition of properties of elements at regular intervals in the periodic table.

18. Front: What are periodic properties?
Back: Properties like atomic size, ionization energy, electron affinity, and electronegativity that show regular variation in the periodic table.

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### Shells/Orbits
19. Front: What are shells or orbits?
Back: Electrons revolve around the nucleus in fixed circular paths called shells or orbits, which are associated with specific energy levels.

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### Valency
20. Front: What is valency?
Back: It is the combining capacity of an atom, equal to the number of electrons an atom can lose, gain, or share.

21. Front: How does valency change in a group and period?
Back:
- Down a group: Valency remains the same.
- Across a period: Valency increases from 1 to 8.

22. Front: Which elements show variable valency?
Back: Transition metals like Cu, Fe, Ag, and Au.

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### Periodic Properties of Elements
23. Front: What is atomic size?
Back: The distance between the nucleus and the outermost shell of an atom.

24. Front: What is metallic character?
Back: The tendency of an element to lose valence electrons and form a positive ion (e.g., Na → Na⁺).

25. Front: What is non-metallic character?
Back: The tendency of an element to gain electrons to attain an octet (e.g., Cl + e⁻ → Cl⁻).

26. Front: What determines chemical reactivity in metals and non-metals?
Back:
- Metals: Greater tendency to lose electrons = higher reactivity.
- Non-metals: Greater tendency to gain electrons = higher reactivity.

27. Front: What is ionization energy (IE)?
Back: The energy required to remove an electron from a neutral gaseous atom.

28. Front: What is electron affinity (EA)?
Back: The energy released when a neutral atom gains electrons to form a negatively charged ion.

29. Front: What is electronegativity?
Back: The tendency of an atom to attract shared electrons in a molecule.

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### Atomic Number and Mass Number
30. Front: What is atomic number (Z)?
Back: The number of protons in the nucleus of an atom, unique to each element.

31. Front: What is mass number (A)?
Back: The sum of protons and neutrons in the nucleus of an atom.

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### Variation of Periodic Properties
32. Front: How does atomic size vary in a group and period?
Back:
- Increases down a group.
- Decreases across a period.

33. Front: How does ionization energy vary in a group and period?
Back:
- Decreases down a group.
- Increases across a period.

34. Front: How does electron affinity vary in a group and period?
Back:
- Decreases down a group.
- Increases across a period.

35. Front: How does electronegativity vary in a group and period?
Back:
- Decreases down a group.
- Increases across a period.

36. Front: How does metallic character vary in a group and period?
Back:
- Increases down a group.
- Decreases across a period.

37. Front: How does non-metallic character vary in a group and period?
Back:
- Decreases down a group.
- Increases across a period.

38. Front: How does the basic nature of oxides vary in a group and period?
Back:
- Increases down a group.
- Decreases across a period (becomes acidic).

39. Front: How does chemical reactivity vary in a group and period?
Back:
- Metals: Reactivity increases down a group.
- Non-metals: Reactivity decreases down a group.
- Across a period: Reactivity first decreases and then increases.

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