For example, the melting points of the trivalent lanthanides (all but europium and ytterbium) are related to the extent of hybridisation of the 6s, 5d, and 4f electrons (lowering with increasing 4f involvement), and lanthanum has the second-lowest melting point among them: 920 °C. (Europium and ytterbium have lower melting points because they delocalise about two electrons per atom rather than three.) This chemical availability of f orbitals justifies lanthanums placement in the f-block despite its anomalous ground-state configuration (which is merely the result of strong interelectronic repulsion making it less profitable to occupy the 4f shell, as it is small and close to the core electrons).The lanthanides become harder as the series is traversed: as expected, lanthanum is a soft metal. Lanthanum has a relatively high resistivity of 615 nΩm at room temperature; in comparison, the value for the good conductor aluminium is only 26.50 nΩm. Lanthanum is the least volatile of the lanthanides. Like most of the lanthanides, lanthanum has a hexagonal crystal structure at room temperature. At 310 °C, lanthanum changes to a face-centered cubic structure, and at 865 °C, it changes to a body-centered cubic structure. Chemical
As expected from periodic trends, lanthanum has the largest atomic radius of the lanthanides. Hence, it is the most reactive among them, tarnishing quite rapidly in air, turning completely dark after several hours and can readily burn to form lanthanum(III) oxide, La2O3, which is almost as basic as calcium oxide.
Generally, the symptoms of NPD also impair the persons psychological abilities to function socially, either at work or at school, or within important societal settings. The DSM-5 indicates that, in order to qualify as symptomatic of NPD, the persons manifested personality traits must substantially differ from social norms. ICD-11 and ICD-10
In the International Statistical Classification of Diseases and Related Health Problems, 11th Edition ICD-11 of the World Health Organization (WHO), all personality disorders are diagnosed under a single title called "personality disorder". The criteria for diagnosis are mainly concerned with assessing dysfunction, distress and maladaptive behavior as opposed to attributing specific personality traits. In the previous edition, the ICD-10, narcissistic personality disorder (NPD) is listed under the category of "other specific personality disorders". This means similarly to the ICD-11, the ICD-10 required that cases otherwise described as NPD in the DSM-5 would only need to meet a general set of diagnostic criteria. Associated features
People with NPD exaggerate their skills, accomplishments, and their degree of intimacy with people they consider high-status. A sense of personal superiority may lead them to monopolize conversations, look down on others or to become impatient and disdainful when other persons talk about themselves. This behavior correlates to an overall worse functioning in areas of life like work and intimate romantic relationships.People with NPD have been observed to use psychosocial strategies, such as the tendency to devalue and derogate and to insult and blame other people, usually with anger and hostility towards peoples responses to their anti-social behavior.