Atomic radius and electrons because opposite charges attract, and more protons creates a stronger charge. The greater attraction draws the electrons closer to the protons, decreasing the size of the particle. Therefore, atomic radius decreases. Down the groups, atomic radius increases. This is because there are more energy levels and therefore a greater distance between protons and electrons. In addition, electron shielding causes attraction to decrease, so remaining electrons can go farther away from the positively charged nucleus. Therefore, size (atomic radius) increases. The following table summarizes the main phenomena that influence the atomic radius of an element: The electrons in the
Unique Particle Attribution which disambiguates it by saying that when an element matches both an element particle and a wildcard, the element particle wins. However, the UPA constraint itself remains in version 1.1. Unique Particle Attribution The Unique Particle Attribution (UPA) rule is a mechanism to prevent ambiguity in W3C XML Schema version 1.0. Due to the UPA rule the XML schema fragment given below is prohibited: Given the XML instance fragment: it is ambiguous whether <x> should be associated with the element declaration (xsd:element name="x"), or the wildcard (xsd:any). This ambiguity violates the UPA rule and the corresponding XML schema therefore needs