Summary & Quick Quiz പീരിയോഡിക് ടേബിൾ
The whole chapter on one page: the table in one picture, the key boxes of the textbook, every rule you need to find a group or a period, the families, the counts and ranges, the size trends, the mistakes to avoid, flashcards, a scored quiz and your study checklist.
1. The whole table in one picture
👆 Click any element to see its configuration, period and group.
Rows are periods (പീരിയഡുകൾ), columns are groups (ഗ്രൂപ്പുകൾ). The two rows at the bottom belong to periods 6 and 7 (the dashed cells in group 3 point to them). Scroll sideways on a phone.
2. The key boxes of the textbook
The chemical and physical properties of elements are periodic functions of their atomic numbers. – page 4
The horizontal rows of the periodic table are periods and the vertical columns are groups. Elements in a group show similarity in chemical and physical properties. – page 5
The elements of groups 1 and 2 and of groups 13 to 18 are called main group elements. – page 6
In a period, from left to right, main group elements gain one more electron in the outermost shell, until it has 8. – page 6
- similar properties within a group
- include metals, non-metals and metalloids
- represent different physical states (solid, liquid, gas)
– page 6
For the elements of groups 1 and 2, the number of electrons in the outermost shell is the group number. (Groups 13–18: outermost electrons + 10.) – page 6
The number of shells in the atoms of an element is its period number. – page 6
Because they have a stable electron arrangement, group 18 elements normally do not take part in chemical reactions. – page 7
Groups 3–12 show the gradual change (transition) from the highly metallic group 2 elements to the less metallic elements from group 13 onwards. – page 7
In the 10 groups 3–12, electron filling takes place in the shell just inside the outermost shell. – page 7
Transition elements in a period generally have the same number of outermost electrons, so they are similar in chemical properties along the period too. – page 7
- groups 3–12
- filling in the penultimate shell
- similar in groups and in periods
- all are metals
- their compounds are generally coloured
– page 7
Lanthanum and the next 14 (La 57 → Lu 71) are the lanthanoids; actinium and the next 14 (Ac 89 → Lr 103) are the actinoids. They are placed separately below the table. – page 8
Down a group the nuclear charge increases, but the number of shells increases enough to outweigh it, so the size of the atoms increases. – page 9
Across a period the number of shells does not change but the nuclear charge increases; the attraction on the outermost electrons increases, so the size decreases. – page 9
Down a group the size of atoms increases; across a period from left to right it generally decreases. – page 9
113 Nh nihonium (Japan), 115 Mc moscovium (Moscow), 117 Ts tennessine (Tennessee), 118 Og oganesson (Prof. Yuri Oganessian). All are in period 7. – page 8
Zinc, cadmium and mercury are usually counted with the transition elements, although strictly they are not – you will learn why in higher classes. – page 7
Elements 1–92 occur in nature except technetium (43) and promethium (61). The elements after uranium (92) are man-made, unstable and radioactive. – page 8
The inner electrons reduce the pull of the nucleus on the outermost electrons. This is the screening (shielding) effect. – page 9
3. Facts & rules
📐 Facts & rules card
groups 1 and 2: group number = number of outermost electrons
groups 13–18: group number = outermost electrons + 10 (10 transition groups come in between)
helium (2) → group 18 · same group → same outermost electrons → similar chemical properties
| Configuration | Shells | Outermost electrons | Period | Group | Element |
|---|---|---|---|---|---|
| 2, 8, 1 | 3 | 1 | 3 | 1 | sodium |
| 2, 2 | 2 | 2 | 2 | 2 | beryllium |
| 2, 3 | 2 | 3 | 2 | 3 + 10 = 13 | boron |
| 2, 8, 6 | 3 | 6 | 3 | 6 + 10 = 16 | sulphur |
| 2, 8, 8, 2 | 4 | 2 | 4 | 2 | calcium |
| 2, 8, 8 | 3 | 8 | 3 | 8 + 10 = 18 | argon |
Families (Table 2.2) മൂലക കുടുംബങ്ങൾ
| Group | Family | Malayalam | Examples |
|---|---|---|---|
| 1 | alkali metals | ആൽക്കലി ലോഹങ്ങൾ | Li, Na, K (hydrogen is in group 1 but is not an alkali metal) |
| 2 | alkaline earth metals | ആൽക്കലൈൻ എർത്ത് ലോഹങ്ങൾ | Be, Mg, Ca |
| 3–12 | transition elements | സംക്രമണ മൂലകങ്ങൾ | Sc … Zn, Fe, Cu, Ag, Au |
| 13 | boron family | ബോറോൺ കുടുംബം | B, Al, Ga |
| 14 | carbon family | കാർബൺ കുടുംബം | C, Si, Ge |
| 15 | nitrogen family | നൈട്രജൻ കുടുംബം | N, P, As |
| 16 | oxygen family | ഓക്സിജൻ കുടുംബം | O, S, Se |
| 17 | halogens | ഹാലൊജനുകൾ | F, Cl, Br, I |
| 18 | noble gases | ഉൽകൃഷ്ട വാതകങ്ങൾ | He, Ne, Ar, Kr |
Counts and ranges
| Period | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|---|---|---|---|---|---|---|
| Elements | 2 | 8 | 8 | 18 | 18 | 32 | 32 |
7 periods, 18 groups, 118 elements. Periods 2 and 3 have the same number (8); periods 6 and 7 include the 15 lanthanoids and the 15 actinoids.
| Block | Where | Remember |
|---|---|---|
| main group elements പ്രധാനഗ്രൂപ്പ് മൂലകങ്ങൾ | groups 1, 2, 13–18 | metals, non-metals and metalloids; solids, liquids and gases |
| transition elements | groups 3–12, from period 4 (scandium, 21) | all metals; filling in the penultimate shell; usually 2 outermost electrons (sometimes 1: Cr, Cu); coloured compounds |
| lanthanoids · rare earths റെയർ എർത്ത്സ് | La 57 → Lu 71 (period 6) | the first row below the table |
| actinoids | Ac 89 → Lr 103 (period 7) | the second row below; those after uranium are man-made |
| inner transition elements അന്തഃസംക്രമണ മൂലകങ്ങൾ | lanthanoids + actinoids | 15 + 15 = 30 elements |
| artificial elements കൃത്രിമ മൂലകങ്ങൾ | technetium 43, promethium 61, and all after 92 | after uranium: transuranium elements – unstable, radioactive |
| metalloids ഉപലോഹങ്ങൾ | groups 13–16 | B; Si, Ge; As, Sb; Te – both metallic and non-metallic nature |
Mendeleev and the modern table
| Mendeleev (1869) | Modern (Moseley) | |
|---|---|---|
| Basis | increasing atomic mass | increasing atomic number |
| Isotopes | no separate places (different masses) | one place – same atomic number |
| Argon 40 and potassium 39 | argon before potassium – mass order broken | Ar 18 before K 19 – no problem |
| Merits | similar elements in a group; gaps left for undiscovered elements and their properties predicted; some atomic masses corrected; noble gases fitted in later as a new group | similar elements in one group; knowing one element tells you about its group |
Size of atoms അറ്റോമിക ആരം
Atomic radius = distance from the centre of the nucleus to the outermost shell. Two factors: the number of shells (more shells → bigger) and the nuclear charge (more charge, same shells → smaller).
Approximate covalent radii in picometres (1 pm = 10−12 m). Largest atoms: bottom left of the table; smallest: top right. Noble gases are not compared.
- “Mendeleev arranged the elements by atomic number.” He used atomic mass; Moseley showed that atomic number is the true basis.
- Adding 10 for groups 1 and 2, or forgetting it for groups 13–18. Sodium 2, 8, 1 is group 1; chlorine 2, 8, 7 is group 7 + 10 = 17.
- Putting helium in group 2. Helium’s only shell is full – it is a noble gas in group 18.
- Period number = outermost electrons. Wrong – period number = number of shells.
- Mixing up periods and groups. Periods are the rows (7), groups the columns (18).
- “Atoms get bigger from left to right” or “smaller down a group”. It is the other way round.
- “A larger nuclear charge always means a bigger atom.” With the same shells, more charge makes the atom smaller; down a group the extra shells win.
- Calling every metal a transition element. Sodium, magnesium and aluminium are main group metals. And check a coloured compound for a transition element – calcium carbonate is white.
- Writing 2, 8, 9 for potassium. It is 2, 8, 8, 1.
- “Noble gases react easily.” Their full outer shell is stable – they normally do not react.
- Putting the lanthanoids and actinoids in a period of their own. They belong to periods 6 and 7; only for space are they drawn as two rows below.
4. Flashcards
Click a card to flip it.
5. Scored quiz
Answer all sixteen, then press Check my answers. Each wrong answer shows the page to revise. For number answers type only the number.
6. Your study checklist
Ticks come from “Mark this page as completed” at the bottom of each page.
Next: the model test paper ▶ – attempt it on paper with a timer first, then check with the solved paper.