멘델레예프가 예측한 원소들: 두 판 사이의 차이
내용 삭제됨 내용 추가됨
"Mendeleev's predicted elements" 문서를 번역하여 만듦 |
"Mendeleev's predicted elements" 문서를 번역하여 만듦 |
||
2번째 줄:
== 접두사 ==
멘델레예프는 그가 예측한 원소들에 이름을 붙이기 위해서 [[산스크리트어]]에서 1, 2, 3을 의미하는 접두사인 ''[[wiktionary:१|eka]]''-, ''[[wiktionary:२|dvi]]''-, and ''[[wiktionary:३|tri-]]''를 사용하였다. 같은 [[족 (주기율표)|족]]의 이미 알려진 원소들로부터 몇 칸 아래에 있는지에 따라 접두사가 결정이 되었는데, 예를 들면 [[저마늄]](germanium)은 1886년에 발견되기 전까지 에카실리콘(
접두사 ''eka-''는 멘델레예프의 예측에서 뿐만 아니라 다른 이론가들에 의해서도 사용되었다. [[프랑슘]](francium)은 발견되기 이전에 에카세슘(eka-caesium)으로 불렸으며, [[아스타틴]](astatine)은 에카아이오딘(eka-iodine)으로 불렸다''. ''접두사 <em>eka-</em>는 아직도 [[초우라늄 원소]]를 지칭할 때 가끔 사용되기도 한다. 예를 들어 [[우누녹튬]](ununoctium)은 에카라돈(eka-radon)으로 불리고 있으며, [[운비우늄]](unbiunium)은 에카악티늄(eka-actinium), 또는 드비란타넘(dvi-lanthanum)으로 불리고 있다. 그러나 현재 [[국제 순수·응용 화학 연합]](IUPAC)는 이러한 접두사들을 사용하는 것 대신에 [[원자번호]]에 기반을 둔 [[체계적 원소 이름]]을 사용하기를 원하고 있다.
== 원래의 예측 ==
[[희토류 원소]]들보다 가볍다고 예견되었던 네 개의 예측된 원소들인 에카붕소(ekaboron, Eb), 에카알루미늄(ekaaluminium, Ea), 에카망가니즈(ekamanganese, Em)과 에카실리콘(ekasilicon, Es)는 각각 [[스칸듐]](scandium), [[갈륨]](gallium), [[테크네튬]](technetium), [[저마늄]](germanium)의성질을 예측한 좋은 예시가 되었으며, 이들은 멘델레예프의 원소주기율표에 포함되었다. 희토류 원소들은 산화된 상태로 발견되기 때문에, 희토류 원소를 얻기 위해서는 그들을 환원시켜야 한다. 그러나 초반의 원소주기율표가 만들어졌던 시점에서는 그러지 못했기 때문에, 멘델레예프의 무거운 원소들에 대한 예측은 엇나가기 시작했고, 그것이 문서화되지도 않았기 때문에 잘 알려지지도 않았다.
스칸듐은 1879년 후반에서야 라르스 닐손(Lars Fredrick Nilson)에 의해서 산화스칸듐으로부터 얻을 수 있게 되었고, 그는 멘델레예프에게 뒤늦게 이 사실을 알렸다. M멘델레예프는 1871년, 에카붕소의 [[원자 질량]]을 44로 예측했었으며, 실제 스칸듐의 원자 질량은 44.955910이었다.
1871년, 멘델레예프는 Mendeleev predicted the existence of a yet-undiscovered element he named eka-aluminium (because of its proximity to aluminium in the periodic table). The table below compares the qualities of the element predicted by Mendeleev with actual characteristics of gallium (discovered in 1875 by Paul Emile Lecoq de Boisbaudran).
{| class="wikitable"
! Property
! Ekaaluminium
! Gallium
|-
| atomic mass
| 68
| 69.72
|-
| density (g/cm<sup>3</sup>)
| 6.0
| 5.904
|-
| melting point (°C)
| Low
| 29.78
|-
| oxide's formula
| Ea<sub>2</sub>O<sub>3</sub> (density: 5.5 g/cm<sup>3</sup>) (soluble in both alkalis and acids)
| Ga<sub>2</sub>O<sub>3</sub> (density: 5.88 g/cm<sup>3</sup>) (soluble in both alkalis and acids)
|-
| chloride's formula
| Ea<sub>2</sub>Cl<sub>6</sub> (volatile)
| Ga<sub>2</sub>Cl<sub>6</sub> (volatile)
|}
[[테크네튬|Technetium]] was isolated by Carlo Perrier and [[에밀리오 지노 세그레|Emilio Segrè]] in 1937, well after Mendeleev’s lifetime, from samples of [[몰리브데넘|molybdenum]] that had been bombarded with [[중수소|deuterium]] nuclei in a [[사이클로트론|cyclotron]] by [[어니스트 로런스|Ernest Lawrence]]. Mendeleev had predicted an atomic mass of 100 for ekamanganese in 1871 and the most stable isotope of technetium is <sup>98</sup>Tc.<ref>This is atomic mass number of 98 which is distinct from an atomic mass in that it is a count of nucleons in the nucleus of one [[동위 원소|isotope]] and is not an actual weight of an average sample (with a natural collection of isotopes) relative to <sup>12</sup>C. </ref>
Germanium was isolated in 1886, and provided the best confirmation of the theory up to that time, due to its contrasting more clearly with its neighboring elements than the two previously confirmed predictions of Mendeleev do with theirs.
{| class="wikitable"
! Property
! Ekasilicon
! Germanium
|-
| atomic mass
| 72
| 72.61
|-
| density (g/cm<sup>3</sup>)
| 5.5
| 5.35
|-
| melting point (°C)
| high
| 947
|-
| color
| grey
| grey
|-
| oxide type
| refractory dioxide
| refractory dioxide
|-
| oxide density (g/cm<sup>3</sup>)
| 4.7
| 4.7
|-
| oxide activity
| feebly basic
| feebly basic
|-
| chloride boiling point
| under 100 °C
| 86 °C (GeCl<sub>4</sub>)
|-
| chloride density (g/cm<sup>3</sup>)
| 1.9
| 1.9
|}
== Thorium, uranium and protactinium ==
The existence of an element between [[토륨|thorium]] and [[우라늄|uranium]] was predicted by Mendeleev in 1871. In 1900 [[윌리엄 크룩스|William Crookes]] isolated [[프로트악티늄|protactinium]] as a radioactive material from uranium which he could not identify. Different isotopes of protactinium were identified in Germany in 1913 and in 1918,<ref><cite class="citation book" contenteditable="false">Emsley, John (2001). </cite></ref> but the name ''protactinium'' was not given until 1948. Since the 1950s thorium, uranium and protactinium have been classified as [[악티늄족|actinides]], hence protactinium does not occupy the place of eka-[[탄탈럼|tantalum]] in what is now called [[5족 원소|Group 5]]. Eka-tantalum is actually [[더브늄|dubnium]].
Mendeleev's 1869 table had implicitly predicted a heavier analog of [[타이타늄|titanium]] and [[지르코늄|zirconium]], but in 1871 he placed [[란타넘|lanthanum]] in that spot. The 1923 discovery of [[하프늄|hafnium]] validated Mendeleev's original 1869 prediction.
== Later predictions ==
In 1902, having accepted the evidence for elements [[헬륨|helium]] and [[아르곤|argon]], Mendeleev placed these Noble Gases in [[비활성 기체|Group 0]] in his arrangement of the elements.<ref><cite class="citation book" contenteditable="false">[[드미트리 멘델레예프|Mendeleev, D.]] (1902-03-19). </cite></ref> As Mendeleev was doubtful of [[원자론|atomic theory]] to explain the [[일정 성분비의 법칙|Law of definite proportions]], he had no ''[[아 프리오리와 아 포스테리오리|a priori]]'' reason to believe [[수소|hydrogen]] was the lightest of elements, and suggested that a hypothetical lighter member of these chemically inert Group 0 elements could have gone undetected and be responsible for [[방사성 붕괴|radioactivity]].
The heavier of the hypothetical proto-helium elements Mendeleev identified with coronium, named by association with an unexplained spectral line in the Sun's [[코로나|corona]]. A faulty calibration gave a wavelength of 531.68 nm, which was eventually corrected to 530.3 nm, which Grotrian and Edlén identified as originating from Fe XIV in 1939.<ref><cite class="citation journal" contenteditable="false">Swings, P. (July 1943). </cite></ref>
The lightest of the Zero Group gases, the first in the Periodic Table, was assigned a theoretical atomic mass between 5.3×10<sup>−11</sup> and 9.6×10<sup>−7</sup>. The kinetic velocity of this gas was calculated by Mendeleev to be 2,500,000 meters per second. Nearly massless, these gases were assumed by Mendeleev to permeate all matter, rarely interacting chemically. The high mobility and very small mass of the trans-hydrogen gases would result in the situation, that they could be rarefied, yet appear to be very dense.<ref><cite class="citation book" contenteditable="false">[[드미트리 멘델레예프|Mendeleev, D.]] (1903). </cite></ref><ref><cite class="citation journal" contenteditable="false">Bensaude-Vincent, Bernadette (1982). </cite></ref>
Mendeleev later published a theoretical expression of [[에테르 (고대 원소)|the ether]] in a small booklet entitled, ''A Chemical Conception of the Ether'', in 1904. His 1904 publication again contained two atomic elements smaller and lighter than hydrogen. He treated the “ether gas” as an interstellar atmosphere composed of at least two lighter-than-hydrogen elements. He stated that these gases originated due to violent bombardments internal to stars, the Sun being the most prolific source of such gases. According to Mendeleev's booklet, the interstellar atmosphere was probably composed of several additional elemental species.
== 참고 문헌 ==
{{Reflist}}
| |||