I’m pretty sure it’s A sorry if wrong
Explanation:
Yes, a chemical reaction can happen with only one substance.
A typical example of such reaction is the radioactive decay.
Radioactive decay is the loss of elementary particles from an unstable nucleus, ultimately changing the unstable element into another more stable element. .
When radioactive elements are let alone, they decompose to form stable harmless elements.
An example of radioactive decay is attached in the image below;
When Iodine-131 emits a β particle will produce Xe-131
<h3>Further explanation
</h3>
Radioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles,
- alpha α particles ₂He⁴
- beta β ₋₁e⁰ particles
- gamma particles ₀γ⁰
- positron particles ₁e⁰
- neutron ₀n¹
So for reaction Iodine-131 :

The shape of the sp3 orbitals is tetrahedral.
<h3>What are orbitals?</h3>
The term orbital refers to a region in space where there is a high probability of finding the electron. We know that sometimes orbitals could be combined in order to obtain the orbitals that are suited in energy to participate in chemical bonding. This is known as the hybridization of orbitals.
The sp3 orbital is a hybrid orbital The four hybrid orbitals are directed towards the corners of a regular tetrahedron. Hence the shape of the sp3 orbitals is tetrahedral.
Learn more about shapes of orbitals:brainly.com/question/11793076
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Two 1+ ions are needed in order to balance one 2- ion.