1. What is periodic classification?
Arranging elements by properties.
2. Why classify elements?
To study properties systematically.
3. What is Dobereiner’s triad?
Group of three elements.
4. How did Dobereiner classify?
By similar properties.
5. What is a triad example?
Li, Na, K.
6. Why was Dobereiner’s method limited?
Few elements formed triads.
7. What is Newlands’ Law of Octaves?
Properties repeat every eighth element.
8. Who proposed Law of Octaves?
John Newlands.
9. What is an octave in chemistry?
Set of eight elements.
10. Why was Newlands’ law rejected?
Didn’t fit heavier elements.
11. What is Mendeleev’s periodic table?
Table based on atomic mass.
12. Who created the periodic table?
Dmitri Mendeleev.
13. What was Mendeleev’s basis?
Increasing atomic mass.
14. What are periods in Mendeleev’s table?
Horizontal rows.
15. What are groups in Mendeleev’s table?
Vertical columns.
16. Why did Mendeleev leave gaps?
For undiscovered elements.
17. What is eka-silicon?
Predicted element (germanium).
18. What is eka-aluminium?
Predicted element (gallium).
19. Why was Mendeleev’s table accepted?
Predicted elements correctly.
20. What is a limitation of Mendeleev’s table?
Hydrogen’s position unclear.
21. Why was hydrogen’s position ambiguous?
Resembles alkali metals, halogens.
22. What is another Mendeleev limitation?
Isotopes placement issue.
23. Why were isotopes problematic?
Different masses, same properties.
24. What is the modern periodic table?
Based on atomic number.
25. Who proposed the modern table?
Henry Moseley.
26. What is the modern periodic law?
Properties depend on atomic number.
27. Why use atomic number?
It’s unique for elements.
28. How many periods in modern table?
Seven periods.
29. How many groups in modern table?
Eighteen groups.
30. What is a period?
Horizontal row in table.
31. What is a group?
Vertical column in table.
32. What does period number indicate?
Number of shells.
33. What does group number relate to?
Valence electrons.
34. What is atomic number?
Number of protons.
35. Why is atomic number fundamental?
Defines element identity.
36. What is atomic mass?
Mass of protons and neutrons.
37. Why is hydrogen in group 1?
One valence electron.
38. What are alkali metals?
Group 1 elements.
39. What are alkaline earth metals?
Group 2 elements.
40. What are halogens?
Group 17 elements.
41. What are noble gases?
Group 18 elements.
42. Why are noble gases inert?
Complete valence shells.
43. What is group 1’s valency?
Valency is 1.
44. What is group 2’s valency?
Valency is 2.
45. What is group 17’s valency?
46. What is group 18’s valency?
Valency is 0.
47. What is valency?
Combining capacity of element.
48. Why does valency vary?
Depends on valence electrons.
49. What is atomic size?
Radius of an atom.
50. How does atomic size change in a period?
Decreases left to right.
51. Why does atomic size decrease?
Increased nuclear charge.
52. How does atomic size change in a group?
Increases top to bottom.
53. Why does atomic size increase?
More electron shells.
54. What is metallic character?
Tendency to lose electrons.
55. How does metallic character change in a period?
56. Why does metallic character decrease?
More electrons to gain.
57. How does metallic character change in a group?
58. Why does metallic character increase?
Easier to lose electrons.
59. What is non-metallic character?
Tendency to gain electrons.
60. How does non-metallic character change in a period?
Increases left to right.
61. Why does non-metallic character increase?
Closer to full shell.
62. How does non-metallic character change in a group?
Decreases top to bottom.
63. Why does non-metallic character decrease?
Harder to gain electrons.
64. What is electronegativity?
Ability to attract electrons.
65. How does electronegativity change in a period?
66. Why does electronegativity increase?
Stronger nuclear pull.
67. How does electronegativity change in a group?
68. Why does electronegativity decrease?
More shells, less pull.
69. What is an element’s position?
Defined by period, group.
70. What is lithium’s group?
Group 1.
71. What is lithium’s period?
Period 2.
72. What is sodium’s group?
73. What is sodium’s period?
Period 3.
74. What is fluorine’s group?
Group 17.
75. What is fluorine’s period?
76. What is neon’s group?
Group 18.
77. What is neon’s period?
78. What is magnesium’s group?
Group 2.
79. What is magnesium’s period?
80. What is aluminium’s group?
Group 13.
81. What is aluminium’s period?
82. What is carbon’s group?
Group 14.
83. What is carbon’s period?
84. What is oxygen’s group?
Group 16.
85. What is oxygen’s period?
86. What is electronic configuration?
Arrangement of electrons.
87. What is lithium’s configuration?
2,1.
88. What is sodium’s configuration?
2,8,1.
89. What is fluorine’s configuration?
2,7.
90. What is neon’s configuration?
2,8.
91. What is magnesium’s configuration?
2,8,2.
92. Why is configuration important?
Determines chemical properties.
93. What is a valence electron?
Outermost shell electron.
94. Why are valence electrons key?
They form bonds.
95. How many valence electrons in group 1?
96. How many valence electrons in group 2?
Two valence electrons.
97. How many valence electrons in group 17?
Seven valence electrons.
98. How many valence electrons in group 18?
Eight valence electrons.
99. What is helium’s configuration?
2.
100. Why is helium in group 18?
Full valence shell.
101. What is chlorine’s group?
102. What is chlorine’s period?
103. What is chlorine’s configuration?
2,8,7.
104. What is potassium’s group?
105. What is potassium’s period?
Period 4.
106. What is potassium’s configuration?
2,8,8,1.
107. What is calcium’s group?
108. What is calcium’s period?
109. What is calcium’s configuration?
2,8,8,2.
110. What is boron’s group?
111. What is boron’s period?
112. What is boron’s configuration?
2,3.
113. What is nitrogen’s group?
Group 15.
114. What is nitrogen’s period?
115. What is nitrogen’s configuration?
2,5.
116. What is silicon’s group?
117. What is silicon’s period?
118. What is silicon’s configuration?
2,8,4.
119. What is phosphorus’s group?
120. What is phosphorus’s period?
121. What is phosphorus’s configuration?
2,8,5.
122. What is sulfur’s group?
123. What is sulfur’s period?
124. What is sulfur’s configuration?
2,8,6.
125. What is argon’s group?
126. What is argon’s period?
127. What is argon’s configuration?
2,8,8.
128. What is period 1’s elements?
Hydrogen, helium.
129. What is period 2’s element count?
Eight elements.
130. What is period 3’s element count?
131. What is period 4’s element count?
Eighteen elements.
132. Why do periods vary?
Depends on shell capacity.
133. What is group 13’s name?
Boron family.
134. What is group 14’s name?
Carbon family.
135. What is group 15’s name?
Nitrogen family.
136. What is group 16’s name?
Oxygen family.
137. What are transition metals?
Groups 3 to 12.
138. Why are they transition metals?
Partially filled d-orbitals.
139. What is iron’s group?
Group 8.
140. What is iron’s period?
141. What is copper’s group?
Group 11.
142. What is copper’s period?
143. What is zinc’s group?
Group 12.
144. What is zinc’s period?
145. What is atomic radius trend?
Decreases across period.
146. Why does radius decrease?
Stronger nuclear attraction.
147. What is ionic radius?
Radius of ion.
148. How does ionic radius compare?
Cations smaller, anions larger.
149. Why are cations smaller?
Loss of electrons.
150. Why are anions larger?
Gain of electrons.
151. What is ionization energy?
Energy to remove electron.
152. How does ionization energy change in period?
153. Why does ionization energy increase?
Stronger nuclear hold.
154. How does ionization energy change in group?
155. Why does ionization energy decrease?
Electrons farther from nucleus.
156. What is electron affinity?
Energy change when electron gained.
157. How does electron affinity change in period?
158. Why does electron affinity increase?
159. How does electron affinity change in group?
160. Why does electron affinity decrease?
Less nuclear attraction.
161. What is a metalloid?
Element with mixed properties.
162. What are examples of metalloids?
Silicon, germanium.
163. Where are metalloids located?
Between metals, non-metals.
164. What is silicon’s nature?
Metalloid.
165. What is germanium’s nature?
166. What are lanthanides?
Elements 58 to 71.
167. What are actinides?
Elements 90 to 103.
168. Where are lanthanides placed?
Period 6, separate row.
169. Where are actinides placed?
Period 7, separate row.
170. Why separate lanthanides, actinides?
To simplify table.
171. What is hydrogen’s atomic number?
1.
172. What is helium’s atomic number?
173. What is lithium’s atomic number?
3.
174. What is carbon’s atomic number?
6.
175. What is nitrogen’s atomic number?
7.
176. What is oxygen’s atomic number?
8.
177. What is fluorine’s atomic number?
9.
178. What is neon’s atomic number?
10.
179. What is sodium’s atomic number?
11.
180. What is magnesium’s atomic number?
12.
181. What is aluminium’s atomic number?
13.
182. What is silicon’s atomic number?
14.
183. What is phosphorus’s atomic number?
15.
184. What is sulfur’s atomic number?
16.
185. What is chlorine’s atomic number?
17.
186. What is argon’s atomic number?
18.
187. What is potassium’s atomic number?
19.
188. What is calcium’s atomic number?
20.
189. What is scandium’s group?
Group 3.
190. What is scandium’s period?
191. What is titanium’s group?
Group 4.
192. What is titanium’s period?
193. What is chromium’s group?
Group 6.
194. What is chromium’s period?
195. What is manganese’s group?
Group 7.
196. What is manganese’s period?
197. What is cobalt’s group?
Group 9.
198. What is cobalt’s period?
199. What is nickel’s group?
Group 10.
200. What is nickel’s period?
201. What is bromine’s group?
202. What is bromine’s period?
203. What is krypton’s group?
204. What is krypton’s period?
205. What is rubidium’s group?
206. What is rubidium’s period?
Period 5.
207. What is strontium’s group?
208. What is strontium’s period?
209. What is hydrogen’s nature?
Non-metal.
210. What is lithium’s nature?
Metal.
211. What is fluorine’s nature?
212. What is magnesium’s nature?
213. What is oxygen’s nature?
214. What is aluminium’s nature?
215. What is chlorine’s nature?
216. What is calcium’s nature?
217. What is iron’s nature?
218. What is iodine’s nature?
219. What is iodine’s group?
220. What is iodine’s period?
221. What is xenon’s group?
222. What is xenon’s period?
223. What is cesium’s group?
224. What is cesium’s period?
Period 6.
225. What is barium’s group?
226. What is barium’s period?
227. What is lead’s group?
228. What is lead’s period?
229. What is bismuth’s group?
230. What is bismuth’s period?
231. What is polonium’s group?
232. What is polonium’s period?
233. What is astatine’s group?
234. What is astatine’s period?
235. What is radon’s group?
236. What is radon’s period?
237. What is francium’s group?
238. What is francium’s period?
Period 7.
239. What is radium’s group?
240. What is radium’s period?
241. What is group 3’s nature?
Transition metals.
242. What is group 4’s nature?
243. What is group 5’s nature?
244. What is group 6’s nature?
245. What is group 7’s nature?
246. What is group 8’s nature?
247. What is group 9’s nature?
248. What is group 10’s nature?
249. What is group 11’s nature?
250. What is group 12’s nature?
251. What is sodium’s valency?
252. What is magnesium’s valency?
253. What is aluminium’s valency?
254. What is silicon’s valency?
4.
255. What is phosphorus’s valency?
3 or 5.
256. What is sulfur’s valency?
2, 4, or 6.
257. What is chlorine’s valency?
258. What is argon’s valency?
0.
259. What is potassium’s valency?
260. What is calcium’s valency?
261. What is carbon’s valency?
262. What is nitrogen’s valency?
263. What is oxygen’s valency?
264. What is fluorine’s valency?
265. What is neon’s valency?
266. What is boron’s valency?
267. What is helium’s valency?
268. What is lithium’s valency?
269. What is group 13’s valency?
270. What is group 14’s valency?
271. What is group 15’s valency?
272. What is group 16’s valency?
273. What is hydrogen’s valency?
274. Why is hydrogen unique?
Fits multiple groups.
275. What is beryllium’s group?
276. What is beryllium’s period?
277. What is beryllium’s configuration?
2,2.
278. What is beryllium’s valency?
279. What is arsenic’s group?
280. What is arsenic’s period?
281. What is arsenic’s nature?
282. What is antimony’s group?
283. What is antimony’s period?
284. What is antimony’s nature?
285. What is tellurium’s group?
286. What is tellurium’s period?
287. What is tellurium’s nature?
288. What is selenium’s group?
289. What is selenium’s period?
290. What is selenium’s nature?
291. What is gallium’s group?
292. What is gallium’s period?
293. What is gallium’s nature?
294. What is germanium’s group?
295. What is germanium’s period?
296. What is indium’s group?
297. What is indium’s period?
298. What is indium’s nature?
299. What is tin’s group?
300. What is tin’s period?
301. What is tin’s nature?
302. What is hydrogen’s configuration?
303. What is scandium’s configuration?
2,8,9,2.
304. What is titanium’s configuration?
2,8,10,2.
305. What is vanadium’s group?
Group 5.
306. What is vanadium’s period?
307. What is vanadium’s configuration?
2,8,11,2.
308. What is yttrium’s group?
309. What is yttrium’s period?
310. What is zirconium’s group?
311. What is zirconium’s period?
312. What is silver’s group?
313. What is silver’s period?
314. What is gold’s group?
315. What is gold’s period?
316. What is mercury’s group?
317. What is mercury’s period?
318. What is sodium’s nature?
319. What is potassium’s nature?
320. What is sulfur’s nature?
321. What is phosphorus’s nature?
322. What is silicon’s valency?
323. What is aluminium’s configuration?
2,8,3.
324. What is magnesium’s configuration?
325. What is chlorine’s valency?
326. What is argon’s nature?
327. What is calcium’s valency?
328. What is iron’s configuration?
2,8,14,2.
329. What is copper’s configuration?
2,8,18,1.
330. What is zinc’s configuration?
2,8,18,2.
331. What is bromine’s configuration?
2,8,18,7.
332. What is krypton’s configuration?
2,8,18,8.
333. What is rubidium’s configuration?
2,8,18,8,1.
334. What is strontium’s configuration?
2,8,18,8,2.
335. What is iodine’s configuration?
2,8,18,18,7.
336. What is xenon’s configuration?
2,8,18,18,8.
337. What is cesium’s configuration?
2,8,18,18,8,1.
338. What is barium’s configuration?
2,8,18,18,8,2.
339. What is lead’s configuration?
2,8,18,32,18,4.
340. What is bismuth’s configuration?
2,8,18,32,18,5.
341. What is hydrogen’s period?
Period 1.
342. What is helium’s period?
343. What is neon’s nature?
344. What is fluorine’s configuration?
345. What is boron’s nature?
346. What is carbon’s nature?
347. What is nitrogen’s nature?
348. What is oxygen’s configuration?
2,6.
349. What is sodium’s valency?
350. What is potassium’s valency?
351. What is scandium’s nature?
352. What is titanium’s nature?
353. What is chromium’s nature?
354. What is manganese’s nature?
355. What is cobalt’s nature?
356. What is nickel’s nature?
357. What is bromine’s nature?
358. What is krypton’s nature?
359. What is rubidium’s nature?
360. What is strontium’s nature?
361. What is yttrium’s nature?
362. What is zirconium’s nature?
363. What is silver’s nature?
364. What is gold’s nature?
365. What is mercury’s nature?
366. What is lead’s nature?
367. What is bismuth’s nature?
368. What is polonium’s nature?
369. What is astatine’s nature?
370. What is radon’s nature?
371. What is francium’s nature?
372. What is radium’s nature?
373. What is vanadium’s nature?
374. What is group 1’s nature?
Metals.
375. What is group 2’s nature?
376. What is group 17’s nature?
Non-metals.
377. What is group 18’s nature?
378. What is period 1’s nature?
379. What is period 2’s nature?
Mixed (metals, non-metals).
380. What is period 3’s nature?
381. What is period 4’s nature?
Mostly metals.
382. What is cesium’s valency?
383. What is barium’s valency?
384. What is lead’s valency?
2 or 4.
385. What is bismuth’s valency?
386. What is tin’s valency?
387. What is indium’s valency?
388. What is gallium’s valency?
389. What is germanium’s valency?
390. What is arsenic’s valency?
391. What is selenium’s valency?
392. What is tellurium’s valency?
393. What is iodine’s valency?
394. What is xenon’s valency?
395. What is krypton’s valency?
396. What is bromine’s valency?
397. What is zinc’s valency?
398. What is copper’s valency?
1 or 2.
399. What is iron’s valency?
2 or 3.
400. What is cobalt’s valency?
401. What is nickel’s valency?
402. What is manganese’s valency?
2, 4, or 7.
403. What is chromium’s valency?
2, 3, or 6.
404. What is titanium’s valency?
3 or 4.
405. What is scandium’s valency?
406. What is vanadium’s valency?
3, 4, or 5.
407. What is yttrium’s valency?
408. What is zirconium’s valency?
409. What is silver’s valency?
410. What is gold’s valency?
1 or 3.
411. What is mercury’s valency?
412. What is francium’s valency?
413. What is radium’s valency?
414. What is radon’s valency?
415. What is astatine’s valency?
416. What is polonium’s valency?
417. What is strontium’s valency?
418. What is rubidium’s valency?
419. What is antimony’s valency?
420. What is hydrogen’s group?
421. What is helium’s group?
422. What is vanadium’s configuration?
423. What is yttrium’s configuration?
2,8,18,9,2.
424. What is zirconium’s configuration?
2,8,18,10,2.
425. What is silver’s configuration?
2,8,18,18,1.
426. What is gold’s configuration?
2,8,18,32,18,1.
427. What is mercury’s configuration?
2,8,18,32,18,2.
428. What is tin’s configuration?
2,8,18,18,4.
429. What is indium’s configuration?
2,8,18,18,3.
430. What is gallium’s configuration?
2,8,18,3.
431. What is arsenic’s configuration?
2,8,18,5.
432. What is selenium’s configuration?
2,8,18,6.
433. What is tellurium’s configuration?
2,8,18,18,6.
434. What is antimony’s configuration?
2,8,18,18,5.
435. What is group 13’s nature?
Mixed (metals, metalloid).
436. What is group 14’s nature?
Mixed (non-metal, metalloid, metals).
437. What is group 15’s nature?
Mixed (non-metals, metalloids, metal).
438. What is group 16’s nature?
Mixed (non-metals, metalloid).
439. What is lanthanides’ nature?
440. What is actinides’ nature?
441. What is chromium’s configuration?
2,8,13,1.
442. What is manganese’s configuration?
2,8,13,2.
443. What is cobalt’s configuration?
2,8,15,2.
444. What is nickel’s configuration?
2,8,16,2.
445. What is francium’s configuration?
2,8,18,32,18,8,1.
446. What is radium’s configuration?
2,8,18,32,18,8,2.
447. What is polonium’s configuration?
2,8,18,32,18,6.
448. What is astatine’s configuration?
2,8,18,32,18,7.
449. What is radon’s configuration?
2,8,18,32,18,8.
450. What is group 11’s valency?
451. What is group 12’s valency?
452. What is period 5’s nature?
453. What is period 6’s nature?
454. What is period 7’s nature?
455. What is atomic number’s role?
Organizes periodic table.
456. What is valency’s role?
Predicts bonding behavior.
457. What is metallic trend’s use?
Predicts element reactivity.
458. What is non-metallic trend’s use?
Predicts electron gain.
459. What is atomic size’s use?
Explains bonding trends.
460. What is electronegativity’s use?
Predicts bond type.
461. What is ionization energy’s use?
Shows electron removal ease.
462. What is electron affinity’s use?
Shows electron gain tendency.
463. What is periodic table’s purpose?
Organize element properties.
464. Why study periodic trends?
Understand chemical behavior.
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