Search results
Results from the WOW.Com Content Network
Lanthanum is a chemical element with the symbol La and the atomic number 57. It is a soft , ductile , silvery-white metal that tarnishes slowly when exposed to air. It is the eponym of the lanthanide series, a group of 15 similar elements between lanthanum and lutetium in the periodic table , of which lanthanum is the first and the prototype.
Naturally occurring lanthanum (57 La) is composed of one stable (139 La) and one radioactive (138 La) isotope, with the stable isotope, 139 La, being the most abundant (99.91% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being 138 La, with a half-life of 1.03×10 11 years; 137 La, with a half ...
Here [Ne] refers to the core electrons which are the same as for the element neon (Ne), the last noble gas before phosphorus in the periodic table. The valence electrons (here 3s 2 3p 3) are written explicitly for all atoms. Electron configurations of elements beyond hassium (element 108) have never been measured; predictions are used below.
Configurations of elements 109 and above are not available. Predictions from reliable sources have been used for these elements. Grayed out electron numbers indicate subshells filled to their maximum. Bracketed noble gas symbols on the left represent inner configurations that are the same in each period. Written out, these are: He, 2, helium : 1s 2
Get answers to your AOL Mail, login, Desktop Gold, AOL app, password and subscription questions. Find the support options to contact customer care by email, chat, or phone number.
The electronic configuration of most neutral gas-phase lanthanide atoms is [Xe]6s 2 4f n, where n is 56 less than the atomic number Z. Exceptions are La, Ce, Gd, and Lu, which have 4f n−1 5d 1 (though even then 4f n is a low-lying excited state for La, Ce, and Gd; for Lu, the 4f shell is already full, and the fifteenth electron has no choice ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
The LA Galaxy and New York Red Bulls meet Saturday in the 2024 MLS Cup. Here's what you need to know and how to watch. How to watch MLS Cup: Time, TV, live stream for LA Galaxy vs.