Forment une famille d'éléments chimiques homonyme aux propriétés très homogènes : particulièrement électronégatifs, ils sont chimiquement très réactifs, leur réactivité décroissant lorsque leur numéro atomique augmente
La région située au centre d'un atome constituée de protons et de neutrons (les nucléons).
Il Bombarde du béryllium avec des particules α, remarque une radiation inconnue qui éjecte des protons du noyau. Il en conclut que ces radiations sont composées de particules de masse approximativement égale au proton mais sans charge électrique, les neutrons
Tous des métaux brillants, mous et très réactifs dans les conditions normales de température et de pression. Ils perdent facilement leur électron de valence pour former un cation de charge électrique +1
Il pense que la matière est formée de grains invisibles. Il pense que les atomes sont tous différents et doivent s'emboiter.
Est la plus petite partie d'un corps simple pouvant se combiner chimiquement avec un autre
ils sont blanc argenté, brillants, et chimiquement assez réactifs à température et pression ambiantes. Leur configuration électronique contient une sous-couche s saturée avec deux électrons, qu'ils perdent facilement pour former un cation divalent (état d'oxydation +2).
Une particule élémentaire de spin 1⁄2 qui n'est pas sensible à l'interaction forte.
Down
Les éléments chimiques du groupe 18 (anciennement « groupe VIIIA », voire « groupe 0 ») du tableau périodique.
Les particules appelees electrons qui portent une _____
Une particule subatomique de charge électrique nulle.
Elément chimique dont les propriétés sont intermédiaires entre celles des métaux et des non-métaux ou sont une combinaison de ces propriétés.
En 1805, il suppose l'existence des atomes et déclare qu'ils en existent plusieurs types.
rejette la théorie de Democrite et reprend l'idée des 4 éléments.Il s'appuyait sur le concept des quatre éléments de base de Thalès et affirmait
que les atomes ne pouvaient exister puisque ils sont invisibles à ses yeux.
Est une particule de spin entier qui obéit à la statistique de Bose-Einstein.
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