Lanthanoids, Actinoids and New Elements ലാൻഥനോയ്ഡുകളും ആക്റ്റിനോയ്ഡുകളും
Look at the bottom of the periodic table: two lonely rows of 15 elements sit apart from the rest, like two extra benches outside a full classroom. Where do they really belong? On this page you count the elements of periods 6 and 7, fold the two rows back into the table to see why they are kept outside, meet the inner transition elements, sort the natural elements from the man-made ones, learn how the four newest elements got their names, and collect material for your assignment on the uses of transition elements.
1. How many elements are there in period 6?
പീരിയോഡിക് ടേബിളിൽ 6-ാം പീരിയഡിൽ എത്ര മൂലകങ്ങളാണ് ക്രമീകരിച്ചിരിക്കുന്നത് എന്ന് ശ്രദ്ധിച്ചിട്ടുണ്ടോ? Have you noticed how many elements are arranged in period 6 of the periodic table?
- അറ്റോമിക നമ്പർ 57 ആയ ലാൻഥനത്തിന്റേയും തുടർന്നുവരുന്ന 14 മൂലകങ്ങളുടെയും സ്ഥാനം എവിടെയാണെന്ന് കണ്ടെത്തൂ. Find the position of lanthanum (atomic number 57) and the 14 elements that follow it.
- അതുപോലെ 7-ാം പീരിയഡിൽ അറ്റോമിക നമ്പർ 89 ആയ ആക്റ്റീനിയത്തിന്റേയും തുടർന്നുവരുന്ന 14 മൂലകങ്ങളുടേയും സ്ഥാനം എവിടെയാണ്? Similarly, where are actinium (atomic number 89) and the 14 elements that follow it in period 7?
Use the lab: press Count period 6 and watch the counter. Notice where it has to jump!
Tap any cell to read it. The cells show the atomic number and the symbol; the colours follow the key (സൂചനകൾ) of textbook Fig 2.1. On a phone, scroll the table sideways.
Lanthanum (57) and the next 14 elements (up to lutetium, 71) are placed in a separate row below the periodic table; in the main table only a box marked "57–71 La–Lu" holds their place in group 3 of period 6.
Actinium (89) and the next 14 elements (up to lawrencium, 103) are placed in another separate row, just below the lanthanoids; the box "89–103 Ac–Lr" holds their place in period 7. Period 7 also has 32 elements.
In period 6, lanthanum and the 14 elements that follow it are arranged separately at the bottom of the periodic table. The elements from lanthanum (La, atomic number 57) to lutetium (Lu, atomic number 71) are called lanthanoids (ലാൻഥനോയ്ഡുകൾ).
7-ാം പീരിയഡിലെ ആക്റ്റീനിയവും തുടർന്നുവരുന്ന 14 മൂലകങ്ങളും പീരിയോഡിക് ടേബിളിൽ ലാൻഥനോയ്ഡുകൾക്ക് ചുവടെ പ്രത്യേകം ക്രമീകരിച്ചിരിക്കുന്നു. അറ്റോമിക നമ്പർ 89 ആയ ആക്റ്റീനിയം (Ac) മുതൽ അറ്റോമിക നമ്പർ 103 ആയ ലോറൻഷ്യം (Lr) വരെയുള്ള മൂലകങ്ങളെ ആക്റ്റിനോയ്ഡുകൾ എന്നു വിളിക്കുന്നു.Actinium and the 14 elements that follow it in period 7 are arranged separately below the lanthanoids. The elements from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103) are called actinoids (ആക്റ്റിനോയ്ഡുകൾ).
Press Fold the two rows into the table in the lab. With the 15 + 15 elements inside periods 6 and 7, the table needs 32 columns – almost twice as wide, with tiny cells and large empty gaps above. Keeping the two rows separately at the bottom keeps the table compact (18 columns) and easy to read and print. They still belong to periods 6 and 7: each row fits into the single box of group 3 marked "57–71" or "89–103".
2. Inner transition elements and rare earths (page 37)
ലാൻഥനോയ്ഡുകളും ആക്റ്റിനോയ്ഡുകളും അന്തഃസംക്രമണ മൂലകങ്ങൾ (Inner transition elements) എന്നാണ് അറിയപ്പെടുന്നത്. ലാൻഥനോയ്ഡുകൾ റെയർ എർത്ത്സ് (Rare earths) എന്നും അറിയപ്പെടുന്നുണ്ട്. ആക്റ്റിനോയ്ഡുകളിൽ യുറേനിയത്തിന് (U) ശേഷമുള്ള മൂലകങ്ങൾ മനുഷ്യനിർമിതമാണ്.
- The lanthanoids and the actinoids together are known as the inner transition elements (അന്തഃസംക്രമണ മൂലകങ്ങൾ).
- The lanthanoids are also known as the rare earths (റെയർ എർത്ത്സ്).
- Among the actinoids, the elements after uranium (U, 92) are man-made (മനുഷ്യനിർമിതം).
The shining black sand on the beaches of Chavara–Neendakara in Kollam contains the mineral monazite, which is rich in rare earths. Indian Rare Earths Limited (IREL) at Chavara separates the rare earths from it. The same sands give ilmenite, from which KMML at Chavara makes the white paint pigment titanium dioxide (titanium is a transition element – see section 5).
Use the atomic number: 57–71 → lanthanoid; 89–103 → actinoid. For "natural or man-made", read the transuranium box in section 3 – there is one trap in the lanthanoid row!
3. Natural and artificial elements – transuranium elements (box, page 37)
- The 118 elements discovered so far are included in the modern periodic table.
- Of these, the elements with atomic numbers 1 to 92 are found in nature – except technetium (atomic number 43) and promethium (atomic number 61).
- The elements after atomic number 92 are made artificially (കൃത്രിമ മൂലകങ്ങൾ).
- Artificial elements are less stable (സ്ഥിരത കുറഞ്ഞവ) and show radioactive nature (റേഡിയോ ആക്ടീവ് സ്വഭാവം).
- The elements that come after uranium (atomic number 92) are known as transuranium elements (ട്രാൻസ്‌യുറേനിയം മൂലകങ്ങൾ).
4. The newest elements – how they got their names (box, page 27)
2016-ൽ 4 മൂലകങ്ങൾ കൂടി പീരിയോഡിക് ടേബിളിൽ ചേർക്കപ്പെട്ടു. ഈ മൂലകങ്ങളെ 7-ാം പീരിയഡിൽ ഉൾപ്പെടുത്തിയിരിക്കുന്നു. In 2016, 4 more elements were added to the periodic table. They have been placed in period 7.
| Atomic number അറ്റോമിക നമ്പർ | Symbol പ്രതീകം | IUPAC name IUPAC നാമം |
|---|---|---|
| 113 | Nh | Nihonium നിഹോണിയം |
| 115 | Mc | Moscovium മോസ്കോവിയം |
| 117 | Ts | Tennessine ടെന്നെസിൻ |
| 118 | Og | Oganesson ഒഗനെസൻ |
- Nihonium got its name from the Japanese word "Nihon". "Nihon" is the word used for Japan in the Japanese language; it also means "the land of the rising sun".
- The experiments connected with the discovery of moscovium were done mainly in laboratories in Moscow.
- Tennessine got its name because of experiments in laboratories in the Tennessee region.
- So these three elements are named after places connected with them. But oganesson was named in honour of the nuclear scientist Prof. Yuri Oganessian. This is the second example of an element named in honour of a living scientist. The first was element 106, seaborgium, named as a mark of respect to the American chemist Glenn Seaborg.
5. Assignment: transition elements in our daily life (page 37)
വിവിധ സംക്രമണ മൂലകങ്ങളും അവയുടെ സംയുക്തങ്ങളും നമ്മുടെ നിത്യ ജീവിതത്തിൽ പ്രയോജനപ്പെടുത്തുന്ന നിരവധി സന്ദർഭങ്ങൾ ഉണ്ടെന്ന് നിങ്ങൾക്ക് അറിയാമല്ലോ. ഈ വിഷയത്തിൽ ഒരു അസൈൻമെന്റ് തയ്യാറാക്കൂ. You know that various transition elements and their compounds are used on many occasions in our daily life. Prepare an assignment on this topic.
- Title – e.g. "Transition elements in our daily life".
- Introduction – what transition elements are: groups 3–12, all metals, most compounds coloured (page 7).
- Main part – a table: element (or compound) · symbol / formula · uses · where you have seen it at home, in the farm, in town. Pick at least 8 from the cards below – and add your own observations.
- Pictures – draw or paste pictures (a copper uruli, a galvanised bucket, a steel almirah …).
- Safety and conclusion – one paragraph each. Mention your sources.
- 📄 Lanthanide Wikipedia
The 15 elements from lanthanum to lutetium (the rare earths). - 📄 IUPAC announces the names of elements 113, 115, 117 and 118 IUPAC
The 2016 announcement of nihonium, moscovium, tennessine and oganesson. - 📄 Glenn T. Seaborg – Facts NobelPrize.org
The chemist after whom element 106 is named. - 📄 The Kerala Minerals and Metals Limited (KMML) KMML, Chavara
Kerala's titanium dioxide factory that uses the ilmenite of Chavara beach sand. - 📄 IREL (India) Limited IREL
The company that separates rare earths from monazite sand at Chavara.
6. Check yourself
- Periods 6 and 7 have 32 elements each. Lanthanum (57) and the next 14 elements – up to lutetium (71) – are the lanthanoids; actinium (89) and the next 14 – up to lawrencium (103) – are the actinoids. Both are placed in two separate rows below the table.
- Lanthanoids + actinoids = inner transition elements; lanthanoids are also called rare earths (monazite of Chavara); actinoids after uranium are man-made.
- Elements 1–92 occur in nature except technetium (43) and promethium (61); elements after 92 are artificial, less stable and radioactive – the transuranium elements.
- 2016: Nh 113, Mc 115, Ts 117, Og 118 were added in period 7. Oganesson honours Prof. Yuri Oganessian – the second element named after a living scientist (the first: seaborgium, 106, Glenn Seaborg).