No.
If an element TYPE or attribute name is not specifically declared to be in an XML NAMESPACE — that is, it is unprefixed and (in the CASE of element type names) there is no default XML namespace — then that name is not in any XML namespace. If you want, you can think of it as having a null URI as its name, although no “null” XML namespace actually exists. For example, in the following, the element type name B and the attribute names C and E are not in any XML namespace:
<google:A xmlns:google=”http://www.google.org/”>
<B C=”bar”/>
<google:D E=”bar”/>
</google:A>

No.
If an element type or attribute name is not specifically declared to be in an XML namespace — that is, it is unprefixed and (in the case of element type names) there is no default XML namespace — then that name is not in any XML namespace. If you want, you can think of it as having a null URI as its name, although no “null” XML namespace actually exists. For example, in the following, the element type name B and the attribute names C and E are not in any XML namespace:
<google:A xmlns:google=”http://www.google.org/”>
<B C=”bar”/>
<google:D E=”bar”/>
</google:A>