Periodic table

1. / Nature of oxide of metals.
6. charge / Attractive force by nucleus.
7. triads / Classification of elements with similar properties in group of three elements.
8. / Elements in group 15.
11. / Tendency of atom to attract shared pair of electron toward itself in covalently bonded molecule.
13. / Trend of electronegativity on moving from left to right in periodic table.
16. / They have highly negative value of electron gain enthalpy.
17. / contains elements that have similar physical or chemical properties.
19. arrangement / Elements are arranged in order of increasing atomic weights and represented in cylindrical table.
20. Mendeleev / Inventor of modern periodic table.

2. / Species that contain same number of electrons but different nuclear charge.
3. / Elements in group 16.
4. metals / gases or brittle solids at room temperature and poor conductors of heat and electricity.
5. element / metals in group 3-12.
9. / Positively charged species having smaller size than parent atom.
10. electronic configruation / Property of nitrogen due to which it shows exception behavior with oxygen in regards of first ionization enthalpy.
12. / Trend of Ionization enthalpy down the group.
14. effect / Repulsion by inner core electrons to valence electrons.
15. transition elements / Another name for f-block elements.
18. / a row of elements in the periodic table whose properties change gradually and predictably.