<u>Answer</u>:
Indirect evidence used to study Earth's interior are
- analysis of several seismographs
- location of an earthquake's epicentre
- identification of seismic wave direction
<u>Explanation</u>:
The earth is mainly divided into 3 layers. These are the crust, mantle and the core. Further, the interior part of the earth cannot be studied directly and the direct evidence explains the composition of rocks.
The seismic waves help with the understanding of indirect evidence. The seismic waves are the energy that travels through different layers of the earth.It is caused due to volcanoes, earthquakes, landslides etc. Thus, analysis of several seismographs, identifying the direction the of seismic wave and location of earth’s epicentre helps to study earth's interior.
It would become a negative ion
Answer:
its outermost shell is completely full making it extremely stable.
Explanation:
It only has two electrons in its outer shell so its valence electron configuration is 1s2. Even though it only has two electrons, it is grouped with elements that have eight valence electrons. Helium is still happy because its outermost shell is completely full making it extremely stable.
The elements whose electron configurations end with f electrons are in the Lanthanide and Actinide series: those long series at the bottom of the Periodic Table (see image).
The atoms are adding electrons into f orbitals, but the f electrons are not always the last electrons in the electron configuration.
For example, the electron configuration of Eu is [Xe]6s²4f⁷, but that of Gd
is [Xe] 6s²4f⁷5d.
I have blocked off in <em>red</em> all the <em>exceptions</em> like Gd.
